We launch about 500 changes to search a year, more than a change a day. So if you look at search like a complicated machine, like a giant jumbo jet—although it's probably, in some ways, more complex than that - this is sort of like changing the engines in flight before you land.
It's been fashionable dissing Google recently. Their search has actually been getting massively better since I pinpointed a low point last year. This must-read article explains why.