And how to install every version you want NVM, that's on the user if it didn't work. That's not something different then can happen with PHP or other tools as mysql in the LAMP setup.
Rhel 7 is still alive, supports node 8, maybe 12, but nothing higher officially.
It's fairly normal to run some version of `npm run serve` with a filesystem watcher that will hot-reload changes as they occur so that you can see changes every time you hit :w (or CMD+S or whatever saves a file on your filesystem)
That's equally true of PHP.
Moreover, it's equally true that distros aren't always shipping the latest PHP versions, and that there are similar flamewars surrounding phpenv/pvm as there are nvm/asdf. There are options, and people have opinions. The more ensconced one gets in an ecosystem, the more easy it is to know which tools offer which benefits relative to your needs. None of those decisions are easily made when new to an ecosystem -- Elixir is newish and has enough coalescence around most of the mainstream things, but as someone new to it, if I needed to choose between Cowboy and Bandit, I would have quite a bit of learning required upfront.