The popularity of RH was (and is) driven by its commercial stability. They were the first to support slow-changing releases over timespans that businesses found

The popularity of RH was (and is) driven by its commercial stability. They were the first to support slow-changing releases over timespans that businesses found realistic. In the enterprise, you can't rebuild a server every other year - you must be able to guarantee stability over 5 years at least. This stability gave major developers (like Oracle) a fixed target they could realistically aim to support with closed-source binaries. This way, they became "the" commercial Linux distribution of choice. They've since missed a few boats, but still they've been careful to play only in the areas where real money can be made - and they've quietly steered platform evolution over the long term, effectively calling all the shots (or at least all the shots that matter) in the Linux world for a long time now.