I've heard that a lot but I don't think this is an adequate comparison (yes even with the disclaimer in the next paragraph). First of all because of the relative stability of Fedora, I've been updating my OS since Fedora 29 and every major upgrade is mostly boring. Second, there are some decisions made in Fedora that wouldn't make sense if it was merely a test bed, removing the whole Java stack comes to mind, or more recently the libreoffice debacle.