I never meant to imply that 15-20 minutes in vimtutor would make you a vim wizard, or that you'd remember everything that vimtutor went through. There's no quick and easy answer to switching to something that does things in a fundamentally different way.
Also, I hold some fairly controversial opinions: you don't need dozens of vim plugins; you don't need to compete with vim golf champions; you don't need an extensive configuration.
What you do need is to fully grok the idea of normal mode as an editing language with verbs, objects, and modifiers. Once you "get it" then you have a working knowledge of how to construct "sentences", and learning a new text object allows you to apply pretty much all verbs to it. Same for learning a new verb; you can apply it to lots of things.
Over the years I've learned a lot of interesting vim things and I've forgotten most of them. Because I don't need them every day or even every week. That's ok. The things I remember are things I use often, because they're useful in everyday editing.