Bottom barrel shared hosting companies like www.myhosting.com and www.dreamhost.com top out at about 50/requests/second. Compared to that, 30,000 reqs/sec seems reasonable enough to me.
The promise of the cloud was a goodbye to limits. Deploy to the cloud, and you'll never run out of anything. Ever.
Amazon (, promise of): We add resources faster than you can use them, kthxbye.
Google apps: Hit the once-in-a-lifetime really, really big one, and we'll be serving up 503's to your customers instead of writing invoices to you. Oh, and if it's sustained we might need you to spend critical time re-deploying to a different architecture.
The difference between the two is that Amazon isn't free. Its pay-per-use.
Provided that you stay within the "free" quota, an AppEngine app can be developed/deployed for free.
One is more "hobbyist" than the other. S3/EC2 is used all over the place by professionals, whereas AppEngine has yet to to really achieve that same kind of ubiquity (in terms of developer mindshare).
That is what you get for building your project on a proprietary platform. You are giving control to a third party and you better have a plan how to deal with the associated risk.
Along these lines, it strikes me as odd how people that would want to run open-source software on their own computers are completely content with running closed web applications where they have no freedom and no control at all. It may be the same reason people are willing to pay for bottled tap-water: convenience - it seems to trump other factors (including ethics and morality) by far.
If Google's limits are, somehow, a problem for you.. go get yourself some EC2 servers, or co-locate or.. a hundred other possible things.