I have only streamed for slightly over a year, so I cannot say anything definite about "years-old footage". But I can absolutely see myself going back to that footage when I get nostalgic about any of the games that I've played. Especially with games that you can only realistically play once, like Outer Wilds.
I only have really used it for fighting games and my object was more to look for issues in my game. So there isn’t that much point to looking at very old footage.