Whats the right way to change horses

Never had the bucks to do real audiophile, but put together a nice Hegel H160 , Rel T9i and SF Concerto system that really worked for me for a few years (mostly single artist listening). Now at 70, I'm parting that out on Facebook MP and looking to move to some simple powered speakers. But thinking, wouldn't it be nice if you could just trade-in you're past gear for a new model, like cars. 

I see the same thing with guitars, moving from steel sting acoustic Gibson guitars to nylon string Classical guitars, just no bridge there,,, not complaining, but seems like there should be a business that does that for you, so you don't have to.