Agree. Inbox is an OK product but nowhere close to expectation. It's a product of mixing ideas, not a product of revealing essence.
Daniel Eran Dilger, the apple fanboy had a brilliant observation on John Sculley's Apple:
"In general, Sculley's Apple consistently produced ambitious but unrealistic technology plans that attempted to over-achieve at a price that failed to capture a sustainable segment of the market. " (http://www.roughlydrafted.com/RD/Q4.06/7C942A13-E006-4EBB-A4...)
Yes, I think Larry Page is another John Sculley.
Edit:
Actually I think GoogleX projects are fine, b/c they are in fact PR projects: couple of billions here and there to maintain a hi-tech myth. Money well spent!
The problem is the products like realtime search, Buzz and G+. They are ill designed, poor planed, poor executed and have 0 substance.