I think of subscription streaming more like cable which also never had them. I've seen them for purchased stuff on the iTunes store. But for e.g. Netflix originals that puts it in a tough spot.

The shift to podcasts that the article mentions is a fun one, though; I hadn't looked at it like that. The "sync this with the film" seems like a pain, but I have listened to standalone fully separate ones that I've liked, just never pictured them as "commentary tracks."