Perhaps it's because other meat-free options are so readily available? The major supermarkets all have own-brand vegetarian burgers, sausages, etc., as well as the branded stuff, and of course there is the wonderful Quorn. We're not vegetarians, but most weeks my partner and I eat Quorn products at least twice. We used to eat tofu (around here we can find it in Tesco and Morrison's) but it was so much more work! You don't mention where you are, but it could be regional; I live near a university, so we tend to get stuff like that quite easily in the supermarkets, and I imagine most decent-sized cities will have them too.