As someone with a background in marketing, let me tell you that the RPG self-publication industry is a giant mess. There's no built-in audience or platforms, the market is over-saturated with products, sales are being cannibalized, entry buyers get nearly all their stuff for free which automatically devalues everything else, and then there's the Goliath that is "official D&D products" to be competing against. It's a high-risk, low-payout market; anyone with a modicum of business sense would turn tail and run the fuck away.
I realize something; the OSR/D&D/RPG/whatever industry is exactly akin to the art industry. Like art, it is born of passion and a drive to connect with people. Like art, it's very difficult to eke out a living. Like art, it's almost impossible to tell beforehand if a work will succeed or fail. Like art, for every Rembrandt, there's a million velvet Elvis paintings; for every master, there's a million people following along to Bob Ross (or in our case, Colville and Mercer). It's thankless, it's tough, and anyone with a brush thinks they can do it as well as the best. There's a reason the term "starving artist" exists; it's not a fair industry.
And like all ventures, there is a risk to be taken, be it in time or in money. Yes, it's unfortunate that their audiences have a problem when it comes time to pull out their wallets, and that makes those risks seem extra not-worth-it. Yes, it's a shame that there are good people with genuine passion who do a fuck-ton of work who aren't getting the payout they deserve. Yes, it's sad that the "titans" of our little niche industry are reduced to scraping by, shutting down, or digitally panhandling just to break even. Yes, it sucks that it takes a whole community of people to support ventures like this.
But that's how the world works. That's how people work. You may as well be angry at the sun for setting.
THAT BEING SAID, D&D (and whatever retro-clone you prefer) would not exist today if it weren't for people whose work is driven by a passion to create something from nothing. Short of the WotC writing staff, the vast majority of people who make things for our little hobby do it not because they expect to make big pay, but because they love the game and they love to create. Gygax and Arneson didn't go into this expecting to become millionaires; they did it because it they had the necessary passion for it. As did everyone who followed them to make something from nothing... and we should absolutely support that. Without those kind of passion-driven creators, the whole industry screeches to a halt. It dies.
I am grateful for every person who put their butt on the line to make works for others to enjoy, because I know it is not an easy risk to take. I am thankful that the hardships of reality have not squashed the pure drive that passion brings to keep them writing against all odds; those unsung are literally carrying this hobby, and they have my gratitude.