Its not closed, since the data and code is out for anyone to use typically, you could even fork and create your own. What is different is the incentive to provide storage and compute for others. Over simplified, you lend your storage and compute (that's called mining) and get paid in crypto tokens in return.

Because mostly its all about the coin, there are no users, only speculators... ahhh but build it and they will come mentality rules here!