Your Sun workstation is from the 80's. Just like processing and storage have evolved over 30 years, so has networking tech. There are now datacenters everywhere, PC market is shrinking, and software companies have been porting IP to the Cloud as a reaction.
Chromebook is Google's vision, not mine. I don't know if or when it'll become a standard architecture, but it's an intriguing concept. Heavy lifting gets offloaded so the end user benefits by not having to pay as much for front end hardware. And that's probably why Apple is neglecting the Cloud - their profit comes almost entirely from sales of front end hardware, not from backend services, and not off software that can be ported to the backend. Apple basically needs SaaS to suck to maintain its revenue stream.
With Office Online, not sure what you're referring to. Even though it's integrated with Azure, 365 still runs off a local client. And Pages and Numbers just have crappy little file reader webapps but full functionality isn't hosted in the cloud.