JanSport was always a budget-ish / not great brand from what I remember. I used them, but high quality was never their thing.

Their lifetime warranty used to be taken extremely seriously, and I really don't know what lifetime they were referring to. I had an old external frame pack that was my grandfather's back when my father was a Boy Scout. That pack outlived its buyer, and I was still using at Philmont where they had the same model as a museum piece. One of the zippers broke, and the back mesh was disintegrating, and pretty much as a joke we made a warranty claim. They honored that, circa 2012 or so.

Their schoolbags were pretty great in the 2000s, too. Withstood some serious abuse, though their zippers were notably on the decline. But that was covered by warranty, so it was fine. By the mid 2010's, they were in full decline, and that's about when I stopped recommending their stuff.

Absolutely not the case. Back in the days of exterior frame packs, Jansport was likely one of the best brands anywhere in the world. Incredibly well designed and made.

OTOH, I haven't thought of Jansport as a go-to brand for a serious backpack in 30+ years ...

When I was a kid everyone knew that JanSport was the one to get if you actually wanted your bag to survive. Absolutely one of those things where you'd spend more replacing the cheaper bags over and over compared to buying the JanSport once.