The thing with N64/GameCube/Wii games though when compared to other pop based collectibles, is they have a functionality inherent to themselves that non-collectors pay for. So you have two separate buyer pools competing for supply. Basically, whenever the gamer market takes over for demand on something, I sell without hesitation. I cleared my Gamecube Mario party's and TTYD, and made out like a bandit as far as I'm concerned. I missed out on selling animal Crossing for $100 because I was in COVID lockdown... Remember when Melee was a $100 game too? Good times.
When the gamer demand reaches fever peaks, sell to them. These are some of the most printed games there are, prices won't sustain.
When collectors are pushing a game into a "bubble", you have to be far more savvy regarding what to hold/sell, or accept that you may not be able to find the item "cheap" again if you do decide to sell. I missed the wave to sell spirits and spells for $300 and now look, eBay flooded with new supply given its new valuation.
You just have to be engaged in the market daily and you'll be able to play the ebbs and flows pretty well.