What trend? All I'm seeing here is further centralisation:

Search engines try to fight slop results with collateral damage mostly in small or even personal websites. Restaurants are happy to be on one platform only: Google Maps. Who needs an expensive website if you're on there and someone posts your menu as one of the pictures? (Ideally an old version so the prices seem cheaper and you can't be pinned down for false advertising.) Open source communities use Github, sometimes Gitlab or Codeberg, instead of setting up a Forgejo (I host a ton of things myself but notice that the community effect is real and also moved away from self hosting a forge). The cherry in top is when projects use Discord chats as documentation and bug reporting "form". Privacy people use Signal en masse, where Matrix is still as niche as it was when I first heard of it. The binaries referred to as open source just because they're downloadable can be found on huggingface, even the big players use that exclusively afaik. Some smaller projects may be hosted on Github but I have yet to see a self-hosted one. Static websites go on (e.g. Github) Pages and back-ends are put on Firebase. Instead of a NAS, individuals as well as small businesses use a storage service like Onedrive or Icloud. Some more advanced users may put their files on Backblaze B2. Those who newly dip their toes in self-hosting increasingly use a relay server to reach their own network, not because they need it but to avoid dealing with port forwarding or setting up a way to privately reach internal services. Security cameras are another good example of this: you used to install it, set a password, and forward the port so you can watch it outside the home. Nowadays people expect that "it just works" on their phone when they plug it in, no matter where they are. That this relies on Google/Amazon and that they can watch all the feeds is acceptable for the convenience. And that's all not even mentioning the death of the web: people who don't use websites anymore the way they were meant (as hyperlinked pages) but work with an LLM as their one-stop shop

Not that the increased convenience, usability, and thus universal accessibility of e.g. storage and private chats is necessarily bad, but the trend doesn't seem to me as you seem to think it is

I can't think of any example of something that became increasingly often self-hosted instead of less across the last 1, 5, or 10 years

If you see a glimmer of hope for the distributed internet, do share because I feel increasingly as the last person among my friends who hosts their own stuff