Because Republicans get fucking dog-walked on any issue of any importance. The only things they can ever even come close to claiming "victory" on are irrelevant nonsense that no serious person gives a fuck about.
There are now more bills attempting to "solve" the problem of trans girl's in sports (and it is girls, to be clear, trans boys are never an issue) than there are trans girls in sports. It's fucking pathetic.
The funny thing about that is - it's a solved problem. The reason you heard about it for a while is that they hadn't tightened up the rules yet. As with anything, problems are highlighted, they are studied, and new rules are put into place to account for what was learned. Right wing media of course discovered a boogeyman that was so useful they will be using it for years still, even if it doesn't exist.