I can't really tell when that happened, but 2 years ago you could go to https://google.com and get all your searches over HTTPS. Good for the paranoid about the government snooping on your ISP (hey, that is happening!).
Today I tried and they redirect to http://google.com (without the 's').
The only reason that I see for them doing that is to preserve CPU, since the SSL consumes between 10-20% more CPU than non-SSL responses.
On a different company, similar topic, on MSN Search (https://search.msn.com) you get the message that "this service is currently unavailable".