Could also just be their own tastes evolving. I used to love turn-based combat RPGs and the RTS genre but I’m kinda over both of them now. If game makers lose passion for those kinds of games, then the “it won’t appeal” might even be more of a “I’m not into it, so if I do make it, it won’t be very appealing” than a “no one wants this kind of game”.
Could also just be their own tastes evolving. I used to love turn-based combat RPGs and the RTS genre but I’m kinda over both of them now. If game makers lose passion for those kinds of games, then the “it won’t appeal” might even be more of a “I’m not into it, so if I do make it, it won’t be very appealing” than a “no one wants this kind of game”.