Starting with subs would have sucked the fun out of zaps I think. But I am looking to subs on Nostr now that the basic infrastructure and user community has been established

But neither have actually taken off. 99% of nostr users don't have a zap-enabled setup and 95% of those who did set up, only used it for a few days (testing). I think if subs had been a thing, we would be more focused in making the creator economy work instead of just a charity play, which is what zaps are today.