It also may be worth it to pick up the thought of switching to a VPS again. Yes, it's work, and having a system with root access does mean responsibility, but it's also a lot of freedom

Yes - it probably is...
You have nailed the reasons why it hasn't happened yet. Work to migrate all the existing domains and tools that live on them, responsibility for having root access and being able to break things I don't understand and the learning curve needed to make it all happen.

There are similarities to the refactoring I am currently doing - changing an entire site from hard coded to implementing Template. It was a bullet to bite, a learning curve and a fair degree of work but actually, I've found that templates are easier and quicker to create as well as being easier to maintain later on. The reason for refactoring to templates was to be able to implement AB testing into the core of the site but other benefits have been found for which I shall be eternally grateful to The Monastery.

I plan to set up a Linux box at home and start using it for some of my everyday tasks - mostly as a learning resource. It's something that I have not got around to yet...