I love Vue as well. The problem is that I haven’t found a good way to fit Vue in with an existing Rails app without it resorting to JavaScript hell. Stimulus looks interesting because it already fits in with Turbolinks.
When you say JS hell I'm assuming you mean because Rails wants to be your JS bundler? Why not just have rails output a div with an ID? And then use a separate bundler such as webpack to generate a JS bundle?
At the end of the day Vue-cli or create-react-app ultimately just generates static assets. Adding your statically built SPA into a Rails app should be no harder than adding jQuery. Rails should not need to know about webpack & vice versa. The key is to build components not a full fledged SPA. Pick either Rails or Vue router. If the former, Vue is just a component/view library, don't treat it like a framework.
Of course, Rails 5.1+ supports webpacker better too, which I believe is recommended/intended for use with stimulus+Rails too (to get the es6 in the example, for instance).
At the end of the day Vue-cli or create-react-app ultimately just generates static assets. Adding your statically built SPA into a Rails app should be no harder than adding jQuery. Rails should not need to know about webpack & vice versa. The key is to build components not a full fledged SPA. Pick either Rails or Vue router. If the former, Vue is just a component/view library, don't treat it like a framework.