Where can I get information about the TODAY'S economic model of the project, and especially - what is the economic benefit from launching and supporting the nodes ?
There was a reward program for those who run full ARDOR node :
https://www.jelurida.com/news/ardor-and-nxt-node-rewards-are-here which was designed to run for 6 months starting from April 1st. Probably it is over at this point but I think you can communicate with Jelurida support and ask them directly about that.