πρεσβύτερον is comparative; and may only mean ‘more important” than the rest.
ἥγηνται is perfect tense, “they have regarded”
“which is why he (Homer) says he’s actually the lord.”
And the scholium doesn’t surmize, it states.
I believe that the perfect form for ἥγηνται is normal, and that it wouldn’t have any noticeable perfect “have believed” English significance.
Here, for example, in Herodotus 2.40 it isn’t talking about the Egyptian history of belief. It’s talking about what they believe now and shows up right next to a present verb: