That's pretty much exactly the way I see it happening. Of course, given healing factors, it would be a while down the road, and with a few false starts, but that's how it'd happen.

I tend to see them probably staying in the Mansion, at least part of the time, because even retired, they'd both need to be a part of things. Steve would help train the new youngsters, and Tony would help out with the tech stuff, and after a lot of yelling, they'd eventually accept that 'retired' meant that they weren't supposed to suit up every time something happened.

Actually, they'd be kind of like Jay Garret and Alan Scott from the JSA.