Pretty sure that is entirely an unfair comparison. You don't need a connection per thread either. It is common to have web servers handles thousands of requests per second with a connection pool size of 20. As long as the handler threads borrow a connection for only a little time and block waiting for a connection while other threads are doing their thing, it works out fine.
There is absolutely no logical reason why database pool sizing could be a reason for preferring fibers over threads.
There is absolutely no logical reason why database pool sizing could be a reason for preferring fibers over threads.