The question is somewhat tongue-in-cheek, especially since I'm (unfortunately) not even running a game at the moment, but it is something I wonder about.
As far as I can see, the majority of M&M players tend to really like designing and building characters, and that extends to GMs too. I've only run a few scattered sessions of M&M here and there, but I've gotten familiar with the rules and am currently putting together a setting and an ever-expanding roster of characters for a game I hope to run in the future, you know the drill.
However, any decent GM can probably tell you that making the PCs sit and watch while your precious NPCs act cool and fight each other for extended periods is generally in bad taste, and rightfully so. "DMPCs" are particularly infamous in D&D circles, for instance. Villains get to show off when the heroes fight them, obviously, but fellow heroes and supporting characters aren't expected to get much spotlight: the focus should generally be on the PCs, and even if NPCs have their cool fights "off screen", the players obviously won't get to see those. There's only so many ways you can make the heroes fight each other before it gets old, too.
The most obvious answer is to do big fight scenes where the allies act as backup against a large group of enemies, but those might get bogged down by numbers; alternatively, in a perfect world, the players think the NPCs are cool too and don't mind taking a short breather to watch them duke it out. Perhaps the NPCs are already on the scene and trying to hold back the villain when the PCs finally arrive to relieve them. I've even considered the idea of letting the players spend a hero point to summon timely backup (if plausible and not story-breaking given the circumstances; probably restricted to big widespread battles where they can't all gang up on the same villain) so they won't feel like the GM is forcing the NPCs on them, but I dunno if that's workable.
Ultimately though, any hamfisted attempt by the GM to move the attention onto their NPCs can come off as a bit self-indulgent, even if understandable. I don't assume this is a game-breaking issue around most tables - especially as I have little experience with hands-on play - but I am curious if people have any views and/or experiences on it, whether as a GM or as a player.