I'm gonna be honest, the talk in the latest chapter of how things were when All for One was active and his prime makes a lot of the series' worldbuilding up to this point feel like a wee bit of a lost opportunity.
Like, saying that having a strong quirk makes a person such a target for him they had to cultivate One for All through people with understated or no quirk at all reads to me like it was a very real and omnipresent risk that people were being targeted and robbed by this big, well-known villain as recently as five years ago. In that kind of scenario, if you'd been born with a strong or flashy quirk, wouldn't you be terrified of showing it off and being known for it? Rather than encouraging pride and making a quirk part of your identity, wouldn't parents encourage their kids to be secretive about their powers and stay out of the spotlight to avoid being targeted? Five years is not a long enough time for a culture to forget what it's like to live that way. Not even close.
Imagine an alternative Hero Aca universe that's going through its first generation of young adults after this protracted war with the quirk-stealing big bad. All Might has stepped up and won the day and he's confident in his power. He's happy to show off what he's able to do to protect the world and people are starting to come out of their shells and feel good about having quirks again. Some of the old timers tell the kids to be more humble and conservative just in case, but the young heroes don't remember living in fear the way the adults do. UA's results are respected, but it's attitude - the Plus Ultra, exceptionalist way of thinking - is frowned on. It's something of a counterculture for the school to be so proud and so public, but it's appealing to the young ones who don't see why they should have to hide themselves. Imagine a society in the middle of the tumultuous process of social change, one that's recovering from a significant shared trauma.
Imagine AU Deku feeling even more conflicted about taking One for All because of the enormous social implications of one man taking another's quirk. Without All Might's power to protect them, how can his world feel like they're able to safely explore their quirks? How would you feel to be the one to take that away and risk being too weak to carry it forward?
Horikoshi could have set up some really interesting social and intergenrational conflicts if he'd taken the chance to really think about how All for One affected the culture he terrorised, and having the effects of his reign in the story from an early stage would have been great foreshadowing for his return and better advance setup for all the stuff we're currently learning. Ah well, he's still doing a great job, I just had a flash of inspiration from these latest revelations.