Most decades will always struggle against the 80's.You have to take into account that it was still a mainstream sport with terrestrial TV coverage up to the mid-90's. I think there's been a slow but gradual decline since then.
I'm not to sure, I remember watching a post fight Ali Interview, and I recall him saying that Boxing was a "Dying Sport". I dont think anyone can pinpoint the highpoint of boxing.
You could make an argument for that and it was the great era for HW's but the 80's had the full package,the four kings,Chavez and Iron Mike. And there was much much more.