I think the Roosters have an excellent squad, and are very well coached.
And have been like that for a number of years.
But I don't think their squad "on paper" is leagues ahead of other clubs. Melbourne, Souths, and Sharks have had pretty consistently good squads for a number of years also, and other squads like Cowboys, Broncos and Panthers at times have had at least a core group of elite players where you think they can be (and should be) competitive.
Knights in the past and Bulldogs right now, have had terrible squads, and many others are or have been poor, but Roosters being much better than those squads is more a reflection of how poor those squads are than how good the Roosters are.
Last year everyone said the Roosters had poor forwards (compared to the other good sides) right up until the finals, when their forwards showed how tough to get through they were. But even so, they don't look as "expensive" a pack as others. Their spine is of course magnificent, but that shows where they have put the most effort, salary cap wise.
They have had Politis and a good stable off field team for decades, but that hasn't turned them into a super club. And Manly were a "super" club of the late 2000s/early 2010s despite being a disaster off the field and not rolling in wealth.
I think it is pretty clear some astute coaching and some elite players staying at a club for a while are what make a club "super", and Roosters have those at the moment, and will lose those at some point and go back in the cycle like all other clubs (unless they keep Robbo for a Bellamy like stint).