I fear SMTP is going to go the way of RSS at the hands of these giant corps. Closed protocols within machine gun lined walled gardens are the future. Sorry old idealistic computer hipies, we've failed you.
I think that the parent is talking about how much power Google has over mail delivery within its own system, which encompasses a larger number of people. If Google decided to switch to a non standard protocol, then smtp'ers would be left high and dry as Microsoft and Yahoo possibly follow suit to maintain an advantage.
Speculation of course but it does point out the problem with Google becoming too big.
SMTP is the only mainstream mail protocol that leaves the end user in control. That must bug companies like Google something fierce.
I still run Outlook 2010 with Paul Graham's SpamBayes plugin. It's far from perfect -- a whitelist would sure be nice, and how hard can it be to automatically refrain from marking anything as spam if I've emailed that sender before? -- but the fact that I can train it myself and adjust its classification parameters covers a multitude of sins.
I've resisted a lot of peer pressure to use server-side email over the years, both commercial and FOSS. I fully expect to be using SpamBayes in 10 years, probably with a wheezing, clunking copy of Outlook in a VM.
