The problem is maintaining it. If something happens and they honestly don’t know the workings behind the software, then they’re going to have a bad experience trying to fix it, short of hiring someone to do it, ie shared hosting.
I think perhaps something will be built in the future. A hybrid of shared hosting and VPS. Where you have the power of VPS but with the shared hosting sysadmin.
Not to mention maintaining it and being responsible for everything else, like VPS security.