"Asura is Pre-Skip man, Oda is not bringing it back" was ALWAYS just because they knew if Zoro used Asura, they could never claim he went all out prior to it. Same deal with Black Blades being "forgotten" it is literally all Agenda brain rot and cope / outright trolling.
The implication WHY nobody BUT Mihawk and Ryuma got black blades is obvious. People just dont want them to be stronger than all of the guys who fail to blacken their blade. Shit, people outright gaslighted themselves over Ryuma somehow being below ODEN, the SWORDSMAN who explicitly DID NOT blacken Enma. Not to even mention Roger, the dude who named his own son after his sword supposedly not giving a shit about swordsmanship / not being a swordsman.
None of the people that say this shit are actually this stupid. I refuse to entertain the possibility they are this ignorant.