He's referring to the fact that, on occasion, the Invite 3200m has gone out slowly. Last year with the 5 sub-4 guys they went out at barely sub-9 pace. There's a few reasons--the race, of course known for the sheer volume of guys sub-9 as you noted, has now become a championship in and of itself. Maybe because of the FL/NXN division or because its at the right time for everyone coming off a winter base? The pace depends on if theres a few guys willing to push or if there is a pacer--in 2023, A. Sahlman brought it through 1600m in about 4:19ish and Birnbaum and co. finished in 8:34.
That being said, I think Jackson Spencer is the typa guy to push it and Mantecon, the Niwot guys, van Meerten all like a fast pace too. More importantly they can KICK off a fast pace, and there's a ton more sub-4:05/ sub-8:50 guys like Lenn, Seitz, Burns, XC guys like Horton... I think we'll see a whole host of guys attached at a 4:17ish opener and many in the low 8:30s this year if the weather cooperates.