Nintendo has billions in the bank. They literallly do have plenty of cash to spare.

The question is, even if they bought Capcom outright, and Capcom could only make games exclusively for their systems from now on, how much of an impact/return on Nintendo's investment, would they really get from Capcom's games?

It's an interesting problem. Personally,  I think NIntendo were fools for not buying Hudson Soft, and keeping that company alive. Konami just absorbed it, killed it off, and have done jack diddly shit with their great properties ever since. Nintendo and Hudson had a great relationship dating back to the NES days. Even when Hudson was the main supporter of the TG16, a direct competitor to Nintendo's consoles, they were still making games for NES/GB/SNES. That really speaks volumes to how good the relationship was between the two. And they always supported Nintendo's systems more than any other, with N64, GC, Wii, etc. Bomberman was put on everything under the sun, but most of their other retail games saw release on Nintendo consoles, usually. And of course there was their hand in creating the Mario Party franchise as well. It just sucks that now Hudson, one of my favorite developers, is now effectively dead because Konami are morons.

But all around, I think there are much more sound and wise company investments Nintendo could/should make. Instead of a big fish like Capcom, Nintendo should buy up some of their smaller partners, such as Level-5, and Next Level Games, and Monster Games, and Platinum, and Good-Feel, and just for fun, Vanillaware, etc.

Monolith Soft didn't bring any IPs with them, so an empty statement.

Do you see Nintendo making a game where you can run around in a mankini beating people up with dildos?  Or a demon fucking another one over a table?  Never going to happen.

Before games like Conker are brought up, they never owned RARE which is why RARE could make such a game.  They're only funding Bayonetta, in a deal that likely got SEGA all the advertising Nintendo is gaving them.