Most of what you're describing is simply an extension of Eternal September. "We" haven't really lost any of these things. It's just that newcomers don't care about them so much.
And that's okay.
Why would I be upset that that some teen or 20-something, who primarily uses the internet to post and browse selfies on social media, does so from a phone rather than a IBM/Lenovo ThinkPad? Their main use case is Instagram or TikTok. A ThinkPad makes no sense for them. But I can still buy one.
Social media platforms "took over" in the sense of having more eyeballs. But so what? Few if any of those eyeballs are really interested in the things that I'm interested in from websites, blogs, etc. Moreover, websites and blogs are still around, and just as populated as they ever were. It's just that there's a bigger population on social media sites.
There ARE multiple search engines. DuckDuckGo even has good policies. True, none of them may be as good as Google. But pretty much ALL of them are better than Lycos, Infoseek, AltaVista, and all of the old-school competitors who lost to Google.
The only thing on this list that's a halfway decent point is Firefox user share. Just to the extent that browser engine monoculture gives Google a lot of power. But as long as the engine is open source, and there's a possibility of more privacy-conscious players leveraging it (e.g. Brave, Vivaldi, etc), then I can live with that.
The "positive" bit about Rust being "the language of the future" gives me the impression that you're mostly mourning geek culture being delegated to a side subculture, instead of being the dominant culture of the Internet itself. To an extent, it is a bummer to no longer be at the forefront of the hype wave. But to be honest, now that I'm middle-aged I don't so much care about being at the forefront of the hype wave anyway. As long as I have my crufty greyboard corner in the Internet's basement, I'm happy. And that doesn't really seem to be going anywhere.