GameStops in my area are actually pretty decent overall. Unfortunately hard to find certain things there sometimes, for example I went to 4 GameStops less than a year ago to get an OEM Switch Dock, and none of them had one. Just Third Party ones that I certainly wouldn't trust. Had to purchase one directly from Nintendo for just over $100. Still, would be sad to see them go, but despite that, I'm aware it'll likely happen at some point, so, I'm ready to resort to Amazon, eBay, etc.
Honestly, I think GameStop should transition to online only. If they start NOW, and if they do it right, they could do well as a major site to find new and used physical games, consoles, etc. I used to use Glyde for used games because they often were cheaper than everywhere else, but at some point they decided to only sell phones and tablets, so... The competition is a bit smaller on the internet these days, at least as far as dedicated gaming products sites are concerned. People don't want to go to physical stores to buy games now, but there's still a good number of those who prefer physical games to digital(myself included, though I'll buy digital if it's on sale for a really good price). An improved GameStop website with more reasonable prices for used games, consistently reliable refurbished systems, accessories, and other goodies, would be a wonderful one-stop-shop for many a gamer. Heck, the website also offers a lot of digital games, so, the potential is already there. A place to buy games, in the format you want? If they just streamlined the site, and made some improvements, it could be a dream come true!