The fee priority mechanism was just node policy. As I recall, miners had mostly all removed it from their nodes so it was eventually removed from the reference client. Developers aren't really in a position to force new fee policies on miners.
they forced segwit......................
No, they didn't.
Miners activated Segwit. If miners were "forced" by anything, it was the threat of BIP 148, which was never part of the reference client. Many Core developers were opposed to merging the UASF -- on such a rushed timeline or at all -- and it never was.
Miners made a conscious decision to activate Segwit to prevent a chain split with users enforcing BIP 148. Core nodes would have sided with majority hashpower either way.
bip9 did not have a august deadline
bip9 would not have caused a controversial split/fork. it would have been an accept or reject. where
if 95% agreed 5% are left receiving stripped data.
if there wasnt an agreement, things just carry on under 2016's ruleset
in short
bip 9 would have meant core devs would have had to put their tail between their legs, and gone back to the drawing board.
however the other bip. forced a fake vote. where nodes had no choice(compatibility) and pools objecting were just not counted/not included in the vote
the august event was not consensus. but as you twistingly admit. miners under threat of an august event where they would end up thrown out the network unless they comply.
if you think that there was no august event. you might want to do some research
the miners conscious decision was not a free choice it was a gun to the head decision to remain conscious on the network or be made unconscious outside the network
secondly you twistingly avoid the fact that core nodes didnt need to have it in because they pre-programmed their nodes to not even get a vote due to "compatibility". meaning the few nodes that would cause a controversial split would just supply the "compatibles" with stripped block data. meaning no need to put it in core because they already done what was needed so that they can shift the blame, while also still wave their hands in the air they want segwit.