Seems like we are talking about different issues.

Regardless of Woz' opinions and incidental hacks, what are real world security assessments of thin computing vs. a system with locally installed apps that have admin privileges?

I think that's the real question.

If there are any (security) benefits to thin computing, then thin computing is a viable alternative to local anti-virus protection, and should be presented as such.

Sure, the cloud is not bulletproof. I never said it was. Still, do you keep your money stashed under the mattress (i.e. local admin access), or put it in the bank ($cloud)?