They're not going to sacrifice the majority and core of their audience for a small percentage of folks on the other side of the country. That would be dumb. Even if it starts at 9:30, you're expecting an entire coast to get off of work, commute either directly to the game or make that pitstop home first, and be in attendance by 6:30, their time? And then you still have the same problem for the EST games, in that they will miss those because they started at 4 PST. 8 & 1030 is fine. You're still getting that maximum window of audience.
If you care about those teams, just stay up or record it. It has been like this for decades.