Security is not the main reason for Bitcoin's success within the cryptocurrency scene, it's that it's the first and most recognizable name. But because its creator is AWOL it's incredibly difficult to push for any fundamental change to the protocol without creating huge divisions and probably a very controversial fork (of which there already have been a few). Unless Satoshi themselves decides to make a comeback, I don't think it'll ever happen.
People are not using Bitcoin because it's the most advanced or secure cryptocurrency, they use bitcoin because it was the first and will probably be the last to go whenever that whole flaming garbage bag of a "technology" hits the bin.