I've heard from multiple independent 3 letter agency associates (past and present) that hackers often often get frustrated and quit US Gov work due to the strict "rules of engagement", that limit offensive operations to critical US infrastructure and government systems.

Often times they know that adversaries are going to attack well in advance and even send advance notice (or retroactive notice) to important targets in some cases. But their operations are, according to them, limited to non-disruptive (though impressive, thorough, and highly specialized) information gathering.

No guarantees that all hands of the government are playing by the same rules, but at least those people's story was pretty consistent.