the economic argument has always been the strongest in my eyes, and it's unstoppable. animals are a huge liability health wise, pollution wise, environment wise, activism wise, logistic wise, etc. most companies don't care about all that stuff at the surface level, but it all translates into dollar signs, which they do care about.
as soon as the economic-taste-weirdness function reaches a certain point, i'll expect you'll see these cheap fast food options convert more and more fractions of their products (right now many use fillers already) to fake meat, eventually replacing it entirely alongside offering reduced prices for these products, while leaving meat generally as a higher priced option signaling disposable income (sort of like Argentinian beef or w/e is today)