Many good Theravada Buddhists in Myanmar seem to feel that there is something mistaken in Mahayana Buddhism. There are differences, as I've described, including doctrinal differences that can be traced to ancient India and differences in style and garb. I would like to suggest that these differences are not so much divergence of doctrine and discipline as they are the awkward re-encounter of diverse cultures: Indian and Chinese. This is particularly important to consider now that we have thrown a third culture into the mix, the Western culture.
Look at a map of Asia and consider: first, in which countries is Theravada Buddhism practiced; second, in which countries is Mahayana Buddhism practiced; third, in which countries have people traditionally (before European colonial influence) eaten with the hands; and, fourth, in which countries have people traditionally eaten with chopsticks. Hopefully you will notice this correlation: Theravada Buddhism dominates in countries which have traditionally been part of the vast Indian sphere of influence, and Mahayana Buddhism dominates in countries that have traditionally been part of the vast Chinese sphere of influence. Tibet and Mongolia, I think, are exceptions, forming an additional cultural area as well as what many consider an additional school of Buddhsim, Vajrayana.
I speculate that two things are going on here: First, the local culture has selected the form of early Buddhism that has most appeal to that culture. Second, the local culture has exerted influence on the Buddhism that it has adopted.
For instance, it has been suggested that Mahayana Buddhism had great appeal in the Chinese because it was so colorful, and had a rich mythology, in contrast to the indigenous Taoism and Confucianism, as well as to the more austere Theravada school of Buddhism. The conditions to which Buddhism then had to adapt were different from its indigenous India: The weather was colder, the emperors were divine beings, there was no tradition of wandering mendicants, family relations were all-important, Pali or Sanskrit was hard to get the tongue around.
The more conservative Theravada Buddhism had a natural base of appeal in the Indian cultural area, but presumably so did early Mahayana. After all, both grew up there. However, cultural conditions would not have been more of a constant, requiring relatively little adaptation over time. Even if Mahayana had come to dominate, which in fact it did in much of the current Theravada area for a long time, it would have been, one would expect, a much more conservative Mahayana than found in the Chinese cultural area. I suggest that the great divergence in Buddhism began when Buddhism reached China. And something similar is now in the process of happening in the West.
How did Buddhism change in China? This is a mix of my understanding and speculation:
First there was the weather: Monks and nuns needed to wear more layers of clothing and daily alms rounds were more difficult.
Then there was the royal family: The emperor was a god. Monks bow down to gods; gods do not bow down to monks. For instance, kings in India were willing to comply with the Buddha's requirements in the Vinaya that prohibited monks from bowing to anyone but more senior monks. Also, some of the colors that Indian monks used to dye their robes were reserved for royal use.
Then, there was Confucianism: The Confucian code of ethics was almost universally observed, I understand, whether or not one was a Buddhist. This provided a framework that to some degree made Buddhist ethics redundant, and to some degree contradicted Buddhist ethics. For example, the family had a dominant place in Confucian culture, while leaving home to become a monk or nun was valued in India. Buddhism adapted by making the family a model of the Buddhist sangha, in which lineage was highlighted. Begging for food was denigrated in China, so the monastic sangha turned to other livelihoods, such as farming and land ownership.
Then there was the government: organizations were distrusted and regulated. More hierarchy was imposed on the monastic sangha, and the simplicity of consensus democracy was diminished or lost.
Then there was Taoism: this provided a new language for Buddhism, well known in Zen, and probably a doctrinal bias toward nondualism and mistrust of conceptual thinking, though this was certainly not entirely new to Mahayana thought in India. More generally the Chinese favored a more synthetic and less analytical approach to doctrine.
Buddhism adapted in China, and in the greater Chinese cultural area, including Japan, Korea and Vietnam, but was not defeated there. It thrived there and in its adaptations discovered new forms of teaching and practice. It is significant that much of what for a long time was considered part of the corpus of Indian Mahayana sutras was in fact composed in China or adjoining areas. The great Zen tradition began in China, in spite of the attribution of a mind-to-mind transmission through Kassapa and Bodhidharma in India. Whereas the bhikkhuni tradition (full ordination for nuns) died out centuries ago in all Theravada countries, it has flourished continuously in Mahayana lands since Sri Lankan nuns brought it to China, around 350 AD.
What are the lessons here for those who traditionally eat with forks? The first is that Buddhism will make many many adaptations to Western culture, making it unlike what we understand now as Theravada or as Mahayana. The culture of West is distinct from both that of India and that of China, though perhaps sharing elements of each. The second is that Buddhism does not thereby have to lose its integrity if we do not lose sight of what Buddhism is all about and if we do not let our very persuasive consumer culture overwhelm Buddhism.
In America, Western Buddhism first sprouted from the Mahayana tradition. A danger in importing Chinese Buddhim is that we thereby accrete adaptations. For instance, Chinese Buddhism has adapted family lineage into Buddhism, but the recitation of the Zen lineage in Western temples I think fails to instill the intended faith in a land where family is probably of less importance that in India or China. I think it is important as Buddhism comes to the West to take stock and understand the history of the tradition. It is particularly important at this juncture to understand as best we can the roots of Buddhism, the teachings of the Buddha as intended for the cultural context in which he lived. But we should not stop there. The Mahayana innovations are partly a result of creative and productive practice, partly a result of cultural necessity, and we should try to understand which is which.
Ultimately the differences between the Theravada and the Mahayana may not really matter so much in the land of the fork, any more that the differences between eating with one's hands and eating with chopsticks. We will develop a Buddhism that is appropriate to our culture, distinct from Indian and Chinese cultural influences, but hopefully retaining what is valuable in both of these ancient traditions.