Brits are never as "famous famous" in Hollywood as American actors. You gotta be best friends with all the studio bosses and Steven Spielberg. Being a part of "them", like Hoffman, is a huge advantage too. Brown nosing is the key to fame in Hollywood.
He was an acclaimed actor in his younger days but he was another in a long line of Brits like Oliver Reed, Robert Shaw, Richard Burton...who struggled with alcoholism. His international breakout role was Hannibal Lecter and he was 53 by then. The other three you mentioned became famous by their late 20's-early 30's. I'm sure that's a big reason why.
The "famous" issue, one would think, is because he is British.
As far as respect, he gets it - he has two Best Actor Oscar wins.
I believe the aforementioned 3 American actors only have one each.
Really, and this part is JMO, all four of these guys are old now. In their primes, some of the best - along with guys like Hackman, Nicholson, Duvall. Hopkins, again, IMO, fits right in with this group.
In terms of respect he’s up there with those legends. Like De Niro he might have taken a dent for being in lots of mediocre films, but he’s still a titan of cinema and will never be forgotten.
The best actors are always the more under-appreciated ones.
To get mass acclaim you need to be in a signature movie everyone loves. Pacino has Scarface, Hoffman has Rain Man and De Niro has Taxi Driver. Hopkins never had that.