Why are there no cross-platform games?

Why are there no cross-platform games? Crossplay would take a lot of control of console sales away from the big companies in the gaming industry. Gamers are likely to just buy whichever console is cheapest if all games get full cross-platform compatibility.

Crossplay would take a lot of control of console sales away from the big companies in the gaming industry. Gamers are likely to just buy whichever console is cheapest if all games get full cross-platform compatibility.