WWE guys are "stars" because they have extended, long term, mainstream exposure. The majority of the AEW talent does not have this for a few reasons.
1. The roster is mostly made up of PWG alum who prior to this had little to no TV exposure, and if they did, it was in smaller tier promotions like MLW and TNA for most of the past 5-6 years. The bigger names they have are former WWE guys or Kenny/Bucks, who gained a following over years with ROH/NJPW/Internet promotion leading to some kind of quasi-"mainstream" notoriety.
2. AEW is new and hasn't had the chance to establish any of these younger, unknown guys on a wider platform. In theory that should be a big selling point: Completely fresh talent that aren't tainted by lame WWE runs that can break out at any time.
So far they haven't done much work to make any of those non-Elite/WWE guys look like stars, so that's something they'll need to improve and focus on immediately going forward and not letting the promotion get bogged down with Jericho's stable vs Cody's stable.