I'm not a developer, but NodeBB is a Node.js application, and Node.js is JavaScript.
So, no, NodeBB does not target "only premium customers who can afford a costly host."
Btw, you can get Cloud hosting that's cheaper than most shared hosting plans. For $5/month, you can get a Cloud server that comes with 512 MB of RAM and a 20 GB SSD storage. If you are really intersted, you can get one at DigitalOcean.