>> I expect google's legal resources are sufficient to discourage plain copying, even if a court case is never won.

Attackers don't care about laws. All they care about their end goal.

You have fraudsters who game the AdWords, reCaptcha etc

Gmail is a strategic tool.

>> the chances of gmail's client side bits doing anything that novel that's also competetively important are slim to none

You are underestimating value of Gmail product. I'm not allowed to share what kind of value the client side has but it certainly does.

>> While there may be a case for DRM in some places, gmail is almost certainly not it.

Again, you are underestimating value Gmail provides to consumers.

This country is a democracy. Companies can obfuscate or de obfuscate code at their wish whether there is value or not.

Privacy people can use Privacy oriented tools or go build their own seriously.

DRM is a billion dollar industry!