Vegetarian food that isn't straight up dried commodities like beans either costs a lot of money or takes a lot of time to prepare in comparison to meat, and the working poor of this country have neither.
It takes exactly the same amount of effort to make vegetarian food as it takes to make a dish with meat, cooking some lentils with vegetables and cottage cheese takes literally twenty minutes for example. And we're currently discussing why meat substitutes are expensive and how to lower the prices.
I can make a complete surf-n-turf meal for a shorter amount of time than that, on top of the fact many people hate things like lentils and cottage cheese. When discussing meat replacements, you have to not just look at cost, but what people are actually willing to eat and take time making when given any choice whatsoever (and most people will choose things that take less time and do not taste like lentils and cottage cheese).
Many people hate surf and turf. How about we don't start a pointless discussion about individual foods when there are endless variations at all levels of preparation complexity both with and without meat?