We should already have our backups in place so adjusting lineups game to game for injuries is unnecessary.
I disagree.
True I can set my preferred backups. But depending who is injured I might like to adjust that. Maybe I have Pennington. I can list him as backup for multiple positions but if I have multiple players get injured which one I would want Pennington put in for might depend on who was injured and who the other bench options are. Plus if one of your backups is also listed as your DH Hal does a terrible job of making that decision. Since the player is already in the starting lineup there is no telling what Hal will do.
But just as important after the decisions have been made of who to play where there is still the decision of how to rearrange the lineup. I may have Pennington listed as backup for Mike Schmidt who is normally my cleanup hitter but I would not want Pennington slotted at cleanup.
I like the idea of having one game a night. It has merit. As to the idea of how much additional revenue might be generated that is more complicated. Changing to 1 game per night would not be a huge programming change. It is already done for playoff games. Just a question of copying that logic over to a regular season league. So minimal cost. It is quality issues like this that could heavily influence for example if I stuck around launching a team or so every week as opposed to just leaving when my current stash of credits are used up.
Some times new features are not just about the profitability of that feature, but also simply improving your product. Anyone who fails to improve their product line over time can expect at some point to start losing customers.