> ...backed up at home and on a Nextcloud instance I keep on a Linode VPS.
> Web is not the only way to read e-mails, friends. Use a proper client and back it up.
I think your advice is good for you and, perhaps, for some of us who are willing to do the work.
But the vast majority of people aren't going to be able to casually fire up, for example, a Nextcloud instance and linode VPS. Not even close.
The long-term management of a DIY personal/household computing infrastructure for email, important files, and online services just isn't in the skill-set of most people who aren't computing professionals. It's not really even in the skill-set of most computing professionals.
I just used Google Checkout to get my music files after Google shutdown the play music service and transferred it to youtube music. I now have ~60GB of zips containing mp3's and meta-data in csv files (admittedly, it was all badly curated by me with garbage id3's and bad filenames). I'm now trying to properly tag and curate these media files and host it in some way that I can use it remotely. It's not a trivial job. Especially because I've decided I don't want surveillance capitalism coming between my music collection and me anymore (eg no spotify/pandora/apple-music for me). I'm sure it's trivial work for some of you but for me to manage a collection of music, it's a challenging project with lots of trial and error (tbh, I kind of enjoy it). Can everyone do this? Definitely not. It's a massive DIY undertaking.
If we're now talking about email and files which are more important that one's cool music collection, it's a whole other ball game. I don't think there's a good solution for those of us who don't want to roll-our-own infrastructure.