Feel free to read my posts above why PvP participation dropped.
And you think people will return to PvP once Mythic raiders take a massive dump over them with their OP Trinkets and Weapons?
I don't mind, i raid mythic, but those "dedicated PvP'ers" might have a thing to say about it.
If the reward structure sucks, people aren't going to do said content, it's that simple.
Imagine if M+ only awarded like 890-910 items, no one would give a shit about it.
If the reward structure in BfA is as bad as in Legion, PvP participation isn't going to increase, because no one wants to enter an imbalanced shitshow that doesn't yield any good loot.