Sure, Google is doing the least-bad thing if you take as axiomatic that you're going to have to store your mail in plaintext on the servers of some enormous American corporation. There are, of course, alternatives that don't involve storing your emails in this way, which is the entire point.
For example, libraries regularly delete library records after a short time as a matter of policy. Mozilla encrypts Sync data with a key known only to the user. These represent alternative approaches that don't have the risks of the corresponding Google services (search and Chrome respectively).
if you actually want others to be able to read your email, it can't be encrypted at some point. PGP et al lost the battle a long time ago, which is pretty much exactly the point here. This isn't just in the US that this is problematic, by the way. Most governments reserve this kind of right for "law enforcement" purposes. For instance:
For example, libraries regularly delete library records after a short time as a matter of policy. Mozilla encrypts Sync data with a key known only to the user. These represent alternative approaches that don't have the risks of the corresponding Google services (search and Chrome respectively).