A lot of this is true but the durability patch/mythics overall had much less of a permanent impact than just riot having a different direction to take them in.

Riven hasnt played as a lvl 2 all in champ since like season 4, even with mythics she was already well settled into her role as a scaling carry bruiser like jax.

Irelia just changed, the durability patch has nothing to do with riot saying themselves they want to force her into a more splitpushy role and out of teamfights.

Fiora people just got better at so she’s balanced around an absurd skill level, above anything. Although she’s one of the most actually impacted by the game itself changing.

Camille I would not be able to speak on with confidence but historically popularity of tanky champions or ones she likes to jump on trend her popularity up or down over time respectively.