I definitely think the trend of paying for online content is becoming more accepted. Consider the "Community Supporter" accounts, not just here at ENWorld, but at other sites, where you get "perks" for putting in a monthly or yearly fee?
Sites like iTunes, Vongo, hell, even Yahoo! Music, are becoming more common because it's becoming more accepted. Society is pretty slow to come around to these concepts and, although the regulars on sites such as this have been here for years, consider even ten years ago and just how common cellular / mobile phones were compared to today. Sure, they have new gadgets and gizmos and sleeker looks, but the technology for reliable mobile phone coverage was there - what was lacking was consumer buy-in.
Online products are moving up in the same fashion. The D20 publishing bubble might have burst due to the inundation of publishers finally reaching critical mass, but the medium of online distribution for RPG content is definitely becoming more viable as people become more accepting of paying for and receiving content via the Internet.
And yes, digital content is far, far easier to work with, update, and distribute than printed material.