This might be true (to some degree) for the recent trend of Western vegetarians, but meat substitutes have a long tradition (over a thousand years) in East Asia due to Buddhist tradition.
Although not many Thais are vegetarians, many do participate in the annual vegetarian festival which comes from Chinese Buddhist tradition. And it is all meat substitutes. There doesn't seem to be much awareness of how to get high quality protein by combining vegetables that contain complementing amino acids. So it's all tofu.
Note that vegetarianism is not a Buddist concept or precept. It is a cultural adaptation in the Chinese version of Buddhism. In fact, vegetarianism was a red herring that the Buddha's jealous cousin used to try to split the sangha.
