I completely agree that the technologies used for self-hosting have been neglected during this era's obsession with what I call the "plain cloud." As you point out, convenience is paramount. The plain cloud has seen the lion's share of R&D and has been sold to consumers as the pinnacle of convenience.
However, I contend that had an equal amount of R&D been invested in a distributed cloud (what we used to refer to as "the Internet," not to be snarky)--especially one that provided federated encrypted data backup among trusted friends and family, a model that would embrace high-bandwidth symmetric connections to consumers' homes and the notion of self-serving--we'd be better off now.
In other threads at HN, I believe this has been covered sufficiently, so I'll cut that short.
I think your first paragraph may be correct insofar as there are many of us who were already doing self-hosting of our data. Those concerned with privacy were already assuming the situation was fairly bad, although I think even we were surprised at how bad it is.
My data is no more interesting than the OP's. Boring e-mail, boring family photos, boring unpopular music, boring documents. Yet out of principal, I self-host it. Self hosting is not that remarkable, but it is a rapidly disappearing practice. As recently as five to ten years ago nearly everyone in the world self-hosted their personal data.
Since my first DSL line in 1998, I've always splurged a bit for a symmetric connection. Since then I've found it disheartening that symmetric connections were and remain marginalized. Today, I can connect to my home VPN relatively easily from any of my devices to access my data. It could certainly be a lot better (I've ranted elsewhere that VPNs suck; they've not seen genuine R&D in ages).
Running a personal mail server is pretty simple too. With so much *-as-a-service out there, I admit that some people are losing the will to install a service of their own, but assuming you do a little bit of research, some modern options are more or less install-and-play, with decent anti-spam.
Again, had a distributed cloud continued to see bountiful R&D as the plain cloud has, the self-managed options would be 5-10 years more mature today. Had Thunderbird not been effectively neglected for the past ~4 years, it would probably be a (slightly) nicer e-mail client.