Nobody is talking about sidestepping laws. You are not breaking laws, nor breaking the spirit of the law, if your users cannot store many years of their personal communications on your server. Encouraging people to delete mail would have the effect of limiting the government's surveillance power, in an entirely legal fashion.
"aren't the laws at fault here?"
It is not that simple. The relevant laws were written at a time when mail quotas were commonly measured in megabytes, when people had to delete their mail in order to stay under the limit. Back then, if a few personal messages happened to be on the server when a court order was received, it was not such a big deal; those messages probably pertained to very recent things anyway. Now, when a court order for "all of Joe's email" is received, that will very likely include messages dating back years, long before whatever crime Joe is suspected of was even committed. The laws have not been updated in light of these new privacy implications.
"If there is an action item on the list, it should be to change unjust laws not to circumvent them. The latter is both defeatist and useless."
Why not do both? Why should we suffer while we wait for the deliberately slow wheels of government to turn? Neither action excludes the other, you can both circumvent unjust laws and work to take those laws off the books.