I'm in the Pacific Time Zone, so most regular season games start at 4 local time. Most playoff games and all WS games start at 5. Playoff games are longer than regular season games, mostly because of pitcher usage but also commercial breaks are longer, so games last until 9 local time. That's midnight eastern time and if I lived in the east I would not stay up that late to watch a baseball game, unless the Tigers were in the game.
I'm a little puzzled by all the concern about start times, because many, if not most, households have DVRs and you can make the game start whenever you want. Just don't watch the news before you want to start the game. I start watching 4 o'clock games about 6, fast forward during commercial breaks and pitching changes, and can comfortably watch a baseball game in under 2 hours.