I feel this way as well. There was a moment in time several years ago where I would see the alt-meat burgers in restaurants and so I would order them from time-to-time because they tasted fine and it didn't kill a cow. Now I hardly see it available, or, if I do, it costs extra.
I think part of the reason they've disappeared from menus is they were setup to fail. Often times the only option for it was just a basic hamburger. Place might have a dozen types of hamburgers but the alt_meat was only an option for the most boring basic cheeseburger