IMO there's nothing you can do to fix this culture. They're determined to ignore the inconvenient problems and then conveniently forget they were told about them. Even if you attempt to document these things, you'll just be labeled some negative name like "whistler blower" or "anal" and the same reputation problems will exist.

FWIW, 2 things mitigate this. First, some companies do actually remember people who fix things and get things done, so that's on your side. The other is that it's not likely you'll be there long-term anyhow. Companies that do this also generally fail in other departments, like paying you what you're worth as your worth increases. So you'll probably look for a new job eventually anyhow.

I know it's hard to see from where you're standing, but I wouldn't fret about it. Just keep doing your job the best you can and warning them, and let the chips fall where they may.