I'm in a similar boat. The last time I really got ponies was in 2013. Since then I've gotten a handful for holidays from family, bought Genie, and only want to buy a couple more of the Project ponies at the moment. I eventually want to complete my goals and get more ponies but its just not a priority for me right now and hasn't been in a very, very long time. Dolls are the same for me right now too. In January I'll hit a decade of doll collecting. I know I'll never stop, still have a wishlist of things I'd like, and wouldn't turn down a gift... but I don't know. There's so many other things going on in my life right now and there's so much other stuff I need to buy that's more important.
However I won't be downsizing because I'm happy with what I've got. I might give some of the toys I've been failing to sell to a local women & children's shelter for Christmas but everything else is fine as it is. Over the years I've done a pretty good job curating my collection to include only ponies I enjoy even if they're not all favorites so thankfully I don't have to worry about regretting anything.