Having a theory of power that doesn't unrealistically imagine a control over government which one demonstrably doesn't have is not "defeatism." Limiting yourself to only one impossible way of doing things is more insidious than learned helplessness, because they can give you a dramatically scripted mini-game to fool yourself into thinking that you're progressing. See slacktivism.

The trouble with controlling the government is that nobody actually does. Nobody will ever get it to do everything they want, or everything it "should", or anything like that. It's a giant uncoordinated bureaucracy full of inefficiency and perverse incentives. Relying only on the government is a time-honored way to die with regrets.

This is not the same as being unable to affect it at all. It can very easily go from being hot garbage to being flaming toxic waste in a tornado when the only people who show up are the ones trying to steal from everyone else.