Thing is, most vegan food are not special. There aren’t tasty ‘vegan burgers’ or whatever. Well there are vegan burgers but none of them are really tasty yet :L. Many people’s vegan food is just your normal food without the meat part. Sunday roast without the meat, so just the potato, mushy peas (or garden peas if you’re more into that), Yorkshire pudding, roasted carrots and turnips, leafy greens, and perhaps a vegan gravy. This combination will keep you alive and strong. In fact if you eat this everyday I guarantee this will make you fat. So to answer your question directly, this is really more like a choice to reduce one subcategory of your diet composition rather than a choice to stop eating one category of food and converting to another.
And yes many vegan burgers are under development, and one of them probably will be tasty enough in a few years. I hope. And lab-grown meat, strictly speaking also vegan, will probably be commercially viable in a couple of decades.
It just isn’t viable. Any vegan (or vegetarian) meal, no matter how good, can have non-vegan additions, and it is always possible to find ones which will improve it. This is simple logic – something formed from a very limited pool of 20% of all possible foodstuffs cannot compete with something that has access to 100%.
I’m not against vegan or vegetarian food, in fact one of the best meals I ever had was a Buddhist temple banquet where everything was vegetarian, and I eat vegetarian meals once, sometimes twice a week, but for my next meal I have the option of the entire range of all food stuffs, and if I was limited to just the very narrow choices of vegan I wouldn’t enjoy that no matter how skilful the menu and preparation.
Notice that the question doesn’t even pretend that the purpose of vegan practices is to produce tasty and complete food for the vegan. It acknowledges the goal is to substitute for foods other people (the omnivores) choose to eat, so the Others can be induced to convert to the Vegan Way. Sounds evangelical to me and the 19th century South Sea missionary societies could have.learnt a lot from these tricky, tricky folk. They even want to coopt commercial food producers to their ends. Hey, we don’t WANT to become vegans, and you can’t make us. You don’t have convincing evidence sufficient to change our tastes and minds and omnivore natures.