This perspective is internally consistent but reveals why IRC struggles without better logging support - the sort of person who is connected and savvy enough to keep logs does fine. Doesn't need them. The people who use IRC are comfortable with that lack.
But the people who use logs won't use IRC, and the people who often miss out on important conversations because they are only casual users will not have logs. Casual users outnumber dedicated users - the lack of good logging is a real problem for them.
I worked in a global team. When I got booted off VPN I would have my irc connection drop and I would miss critical conversations. IRC sucks for collaboration.
I disagree that it's merely a UX deficiency, but I agree that it's not a protocol deficiency. Yes, indeed you could just use an IRC bouncer: the problem is that many users don't have easy access to such a bouncer. What IRC "needs" is a network of open bouncers that users can subscribe to.
But the people who use logs won't use IRC, and the people who often miss out on important conversations because they are only casual users will not have logs. Casual users outnumber dedicated users - the lack of good logging is a real problem for them.