Up to the 3ds games there was always a way to trade pokemon at least 1 generation up (red to silver, silver to ruby, etc) if they continued that trend it should still technically be possible. But eventually you’ll get to a point where it will take long to trade pokemon up than it takea for a new game to come out.
You can’t even ‘catch ‘em all’ anymore anyway. There are too many so they have to keep pulling more and more from the games.
Up to the 3ds games there was always a way to trade pokemon at least 1 generation up (red to silver, silver to ruby, etc) if they continued that trend it should still technically be possible. But eventually you’ll get to a point where it will take long to trade pokemon up than it takea for a new game to come out.