You are right that there is a dockerfile for pretty much everything these days.

However, as an example, I am using Sabre as a CardDAV/CalDAV Server on one of my domains. There is simply no need to spin up an extra container for something simple like this. Same with Matomo for analytics in my comment above, you are just writing a better logfile essentially.

Now Kbin has much more functions than that and I would probably run that in a container as well. For smaller and leaner things, I see shared hosting still as the easier way. When you know that containers exist, you are already in an expert bubble. I would claim that many many people know how to use an FTP client from their Desktop than are able to host a container somewhere - not that I'm a fan of FTP but SCP is already more advanced for that said group I assume.