I used to partake in all RAM discussions online. Here, reddit, every technical hardware forum and anywhere workstations were being talked about.
The sentiment was always ECC is a waste and a scam. My goodness the unhinged posts from people who thought it was a trick and couldn't fathom you don't know you're having bits flipped without it. "it's a rip off" without even looking and seeinf often the price was just that of the extra chip.
I've discussed it for 20 years since the first Mac Pro and people just did not want to hear that it had any use. Even after the Google study.
Consumers giving professionals advice. Was same with workstation graphics cards.
I used to sell workstations and servers years ago and trying to convince people they needed ECC Ram and that it was just insurance for (often) just the price of the extra chips on the DIMMs was a nightmare.
The amount of uninformed and inexperienced counter arguments online suggesting it was purely Intel seeking extra money (even though they didn't sell RAM) was ridiculous.
I never understood why there was so much push back from the consumer world commenting on something they had no idea about. Similar arguments for why would you ever need xxGB of RAM while also condemning the incorrect 640kb RAM Bill Gates comment.
You can buy DIMMs from all three just rare to see in most retail channels for consumer stuff. Obviously Micron have crucial, but you see Micron non-server DIMMs in OEM systems.
Micron, Samsung, Hynix like most others. They aren't reselling ram, just using chips from the only companies that make them, but they pick certain bins and do their own QC and direct support etc.