starcraft 2 had a larger player base because it had 2v2, 3v3, and 4v4.
Gimmick modes that probably less than 5 to 10 percent of the player base actually used regularly? Those modes were pretty much dead soon after launch.
Either way, you could still count that as a basic mutliplayer feature not present in SFV. KOF-style team matches with actual additional players wouldn't be hard to implement. Hell, there are plenty of extra modes that could just be added in. None of this has to be balanced, it's just extra shit that adds to the game.
Player base wouldn't be split if you keep 1v1 as the main matchmaking item and possibly do something like a weekly special mode that's different every time like Overwatch does.
If you say Capcom doesn't have the budget to do shit like this I will say of course they fucking don't. They just spent all that money on this single player garbage.
Also, all them characters and no cosmetic progression. This story mode is literally the first time we've seen relationships and personalities for a bunch of characters in this franchise, too.