Most of parameters there could be changed by witnesses without any hardfork.
By now the majority of top-witnesses have voted for linear rewards and zero minutes early voting penalty.
The actual consensus state can be viewed on explorer https://explorer.golos.io
My understanding why people are still bying votes is some sort of addiction to be on the Trending.
And actually it isn't always 50/90, because vitnesses votes are "split" between something like 25/75, 50/50 and 25/90, consequently the parameters can change a few times a day depending of who from the reserve witnesses is taken into the calculation.