I agree that part of this crossover came from the pop-focused direction Alternative took with Audacy leading the way. Interestingly, though, Audacy’s Alts had shifted away from the Alt-adjacent pop in late 2021. I can only imagine how much higher songs like “As It Was” and “Bad Habit” by Steve Lacy would’ve gotten on the charts had Audacy kept that focus.Considering Harry Styles history, I was kind of surprised, but also not that his music was pushed to Alternative. Surprised, because he came out of a purely pop driven reality TV contest. Not surprised, because he came at a time when the Alternative format was on a heavy pop curve, driven in part by Audacy stations. I truly believe that the pop phase existed to attract females, and also try and broaden the idea of what listeners think of when they hear "Alternative"...
Harry Styles is definitely an odd choice for Alternative given his boy band history and solo pop star success, but I think this specific song fits on a format where Imagine Dragons, AJR, and Glass Animals get a lot of airplay.
In 2014, my wife couldn’t understand why One Republic’s “Counting Stars” wasn’t getting played on Alternative alongside Imagine Dragons, Bastille, Lorde, etc