There is probably a team of non technical folks who are responsible for providing the data ordered by law enforcement/subpoenas, after approval by legal. If Sundar calls the manager of that team and asks for some info, and asks him to keep it off the record for security reasons, what do you think will happen?
A lot of it is encrypted in a way such that they couldn't get the key. The rest of it, technically yes, but they would have to have someone build a feature to give them access.
You mean that someone who builds the feature to give them access, has access to my search history?
No, not even the people who built it would necessarily have access. In practice almost nobody has access to sensitive data, all access is logged and audited, and anyone would get fired if they accessed it inappropriately (i.e. without your consent)