NFL could do with a 2 pre season - 14 game regular season and putting in another round of playoffs with 8 teams from each conference in my opinion.
Greed - pure and simple. Simple fact is 60% of the markets can’t support attendance for all these games.
Baseball for example should have no games on a Tuesday aside from Tuesday night baseball. Take those 20 odd reduced games and do less weeknight games and more 2 game series. Make it special to play on one night a week so teams start their #1 in those games that will be on National TV.
MLB will ADD games if anything. Most stadiums hold 40K+ and being a low impact sport, players can play many days in a row besides pitching. More days in a schedule to fill the stadium = Mucho for MLB team owners.