Non technical people won't use Docker, it's too complicated. Unless you make some environment as easy and widespread as your typical CPANEL shared hosting, you won't compete with PHP for that kind of end-user.

But isn't all cloud offerings basically a better cpanel with docker or kube or whatever?

Don't get me wrong, as a developer I hate the bloat, but as a UX/UI PoV you can install a lot of shit that's dockerized pretty easily...

sandstorm.io is a cool way to self-host open source projects for example

Can I download your non-PHP app, copy and paste into a folder, and get it running after 5 clicks? More important, are the majority of apps of non PHP langs like this?

Most PHP apps out there are dump easy to use. That's not the case even for Python.

I don't use shared hosting anymore (vultr or do mostly now), but I also don't generally use docker...

There's limitations and bloat involved with containers that I don't like. I'd rather just configure nginx/letsencrypt and create some bash scripts to make deployments work...

I'll often pair this with jenkins or come ci or use deployer for deployments that don't tear down the old until the new is green, and keeps a few snapshots, but personally I don't like docker much, even my dev environment uses nginx and no docker.

The absolute minimum amount of knowledge needed for this sort of thing is how to get files onto a server. Lots of people capable of that have absolutely no idea what Docker is or how it works. Lots of people know what it is, and what it does, but have not ever actually used it (like me!). If I was going to install some server software, and saw Docker, it would put me off — great, I have to learn Docker now?

Docker probably is a better way of doing things, but it’s another layer.