I was wondering that myself, what would happen to Nullsoft & Winamp if it was still with AOL now? Wish I bought stock when AOL was spun out...
But tbh, i'm more curious about AIM. I still use it at work (god knows why, but that's what they use) and a part of me never wants to let go of my 17 year old screen name. Still... i'm surprised AIM hasn't gone the way of being merged with another instant messenger (like google since they had the partnership).
Nullsoft was just a legal entity and means pretty much nothing now (as has been the case for a long time).
and it's been clear that AOL was shifting towards advertising aspects for a long time which the likes of Winamp / SHOUTcast / Spinner (which was off comparable heritage) and other things that were killed off / dropped around the same time just didn't fit into the strategy that was being worked on (you can only throw away money for so long before you need to make changes to resolve that issue - as was done).
as for the hypothetical question, if they were still under AOL, by now they'd have likely gotten more adverts into things and I really don't think the likes of Verizon would have any qualms in dropping / killing off little brands and products. or they'd more likely go the other way and requiring payment for everything (as seems to be the way with most of the US telecoms providers).
not that it really matters now as the AOL ship has long since left port.
now the AIM question is more important than the Winamp position due to being a much more used service (though that itself is open to debate depending on how you're looking at what constitutes usage). though it's not like similar services (MSN) haven't seen them being retired, so maybe AIM will go the same way as well... and we instead all use Facebook Messenger *shudders*