Alienstudios lil' infographic sums it up quite well- collecting can become hoarding, but they aren't inherently the same.
For me, the big consideration is useability. Is your collection in boxes, shoved into the corner of a basement, requiring at least an hour of digging & setting up to use? I'm not sure why you keep it & wonder if you're getting ready to cross the line. But dozens of consoles all out, setup, ready to play with the games all just a quick browse away? I don't care how many you have, that's a good collection. It's why I'm so impressed by Joel Hopkins collection- it's not just the biggest in the world, but
it's all accessible! If you haven't seen it:
https://www.youtube.com/watch?v=7sjjGblGtiUYou may argue that so many games is unnecessary, but you can see something in that video that solves that problem for me... the kid, playing the games. I may have more games than I can play- but who says I have to be the one doing the playing? I wish I knew more people who were into retro, so I could let more people play these games I love so much.
I think there's a personality factor too- some people may be off-put by large collections, the clutter is unsettling. That's fine, create a space you can relax in. For me- the clutter IS relaxing. it's kind of like a small secondhand bookstore or a little indie comic shop- all full of history and personality and wonderful things to find and explore and surround yourself in like a warm, fuzzy blanket of sentimentality. I find the deconstructed, minimalist thing to be sterile, cold, and unsettling- like I'm in a store display and not a home. Perspective is funny that way.