I see a lot of people equivalating “easy” with “fun”. I never found collecting easy. That’s why it’s fun.
I've always seen hunting for games as an investment of time and money. I never expected to go to a place like Goodwill or my local flea market and find a bunch of very rare games for next to nothing, however I did expect to find something I was interested in, even if it was some cheap $5 game that had been eluding me. And for several years that expectation was met. Yeah, I did walk away empty handed occasionally, but the hits far outweighed the misses. I'd go out to places like this often and a lot of times wouldn't find anything I was after, but I'd find a ton of games I could use as tradebait or resell for the purpose of putting that money back into collecting.
Around 2013 is when the hits and the misses started to equal out, and then by 2016 it was probably 10% hits and 90% misses, but even given how disproportionate this was I still was motivated to look, albeit not to the extent I used to be. As of the last year and a half, it's been like <1% of the time I go out I'll find something worth picking up; it's literally got that bad for me. Sure I find a ton of games still, but they're all either games I have that are priced above ebay, or are games I do actually want and are priced just as high. At this point I literally have zero reason to continue to go out and look for games when it is nearly certain I won't find anything. Imagine going to a place like Target every week in hopes that they'll have some super obscure movie on DVD there; yes it's possible hey might, but incredibly unlikely, yet you still go back week after week hoping to find it. That's what game collecting became for me, at least the hunting aspect of it. It became way more convenient and cheaper overall just to go on ebay, bite the bullet and pay market value for a game I want. There just isn't enough out there anymore, and what is out there is in the hands of people who absolutely know what they have.
Hopefully this paints a picture of why going from "easy" finds everywhere to it being incredibly hard to even find a copy of Banjo Kazooie priced at $5 under ebay would kill ones motivation to collect and look for games. I don't know when you got into collecting, but it might also be case of knowing how great things once were and comparing them to how they are now that creates this feeling of collecting no longer being fun; if you got into collecting around 2015 or later you really have no idea what you missed out on other than veteran collectors telling you about the good ol'days, which would have little impact on you since you never experienced it first hand.
On the bright side though and as I pointed out in my original post, less and less people are going after these games which at the moment as created a lot more supply while also decreasing prices. Even though these prices are almost always relative to ebay, it's definitely sparked my interest slightly to want to collect some more, but at the same time I have no desire to collect the way I have been for the last 3 or 4 years. If retro games ever slipped into the status of being old junk again then I'd likely get into it again just to buy up games on the cheap and flip so I can buy the stuff I still really want on ebay. But I don't think that'll ever happen again. I think the best that will happen and is actually likely at this point is that retro game prices reflect the games actual abundance and the price reflects this rather than reflecting a massive amount of interest from collectors who want the game so badly that it's caused the price of the game to inflate well past it's quantity in the wild.