I'd agree with your first paragraph in that Node is a bit lower-level out of the box and probably takes more effort to get started building a web-app, but I think the time invested jumping in at that low-level is actually useful vs diving in at a higher 'framework level' with some of the other popular web languages.
Also it does have superior installer/package-manager/deployment stories compared to say ... Python & Django, which does have an impact on ROI.
One of my main use cases for Node is Zombie, and that required io.js after v3. No mainstream PHP, Ruby or Python application has required a different interpreter.
So jsdom 3.x used a lib called "contextify". When io.js was released and the changes included, node support was dropped. Now node 4.0.0 is out and has those changes, jsdom now works on node again.
I see things like this all the time and it really puts me off OSS.
I would say that the ROI is lower for time spent learning Node. I've found that with all the other languages I've learnt, in a couple of days I've been able to build something useful, leave it running in production and reuse skills learned a year later.
With Node, even the name of the language is not stable! A few weeks back I went to install Zombie, and now I have to install iojs and not Node. Assumedly it's now Node again. If you live and breathe the language, subscribe to the mailing lists, go to the meetups, etc, these things might be obvious. But when you're just dipping in and out, it really dents your confidence in the language.