That’s probably because Barristan was, y’know, old when Jaime made that statement. There’s no logical reason for him to talk about a version Barristan that doesn’t exist anymore, especially when Barristan is still alive.
Jaime said that Gerold Hightower was stronger than him in his heyday, yet he didn't know Gerold Hightower during those times. If Prime Barristan was stronger than Jaime, he would have mentioned it like with Gerold Hightower, because there was no reason not to.
Except the statement isn’t Arthur >= Barristan, it’s simply Arthur = Barristan.
But Arthur is still stronger physically than Barristan, for the reasons mentioned above.
Not having the same statements as Robert =/= Robert being stronger than him.
Yes, it is.
If Arthur was as strong as Robert physically, it would have been mentioned at least once, like all other characters and warriors known to be very tall and very strong compared to others. For Arthur Dayne we just know that he was stronger than Jaime and that he fought with a greatsword, compared to Robert who can fight with one hand with a heavier warhammer than Dawn.
No, we shouldn’t, because there’s no reason for Robert to be stronger and there’s no reason for Brienne to be stronger.
For Robert yes, there are reasons, for Brienne too. Both are extremely muscular and physically strong, freakish strong as some characters say, which has never been the case for Arthur Dayne so far. He was very strong yes, but certainly not like Robert Baratheon, Lyle Crakehall, Greatjon Umber, Brienne of Tarth and the Clegane brothers.
Okay, if characters have actually stated that, then it works for Gregor.
Yes:
"She is stronger than I am.
The realization chilled him. Robert had been stronger than him, to be sure. The White Bull Gerold Hightower as well, in his heyday, and Ser Arthur Dayne. Amongst the living, Greatjon Umber was stronger, Strongboar of Crakehall most likely, both Cleganes for a certainty.
The Mountain's strength was like nothing human"
"His armor is so heavy that no lesser man could bear the weight, let alone move in it"
I still see no reason for the Greatjon to scale above all other humans.
Possibly scale above all other warriors, It's the Mountain but a less tall and strong. Just like Gregor Clegane, Jon Umber can easily fight one-handed with a greatsword, and he is the same height as Hodor but he is twice as wide as him.
That’s not what Martin said.
“If both men had equivalent weaponry, it might be a toss-up.”
To have an equivalent sword fight with normal weaponry, they would have to be comparable in strength, because, y’know, that’s how sword fights work.
It's just downscaling, because we already know that Arthur Dayne is superior to Barristan Selmy in strength. Characters who can equalize or defeat opponents stronger than them, it's common in ASOIAF and fiction in general, they don't have to have the same strength.
I have no problems with Ned just being Athlete level so…
Except that Ned is Street level via his fight against Arthur. At least, it all depends on the downscaling, if he still ranks Ned at Street level or downgrades him to Athlete level.
Being able to use a greatsword =/= being equal to other characters that can also use greatswords.
I didn't mean to say that Mance Rayder was equal to Arthur Dayne exactly in terms of physical strength, but that Mance's strength shouldn't be far from Arthur's, as they are physically strong enough to fight with a greatsword. .