So why does the buck stop with government then? If enough of us agree that a law should be passed then why not just pass the law? Seems way easier to just make a rule than try to individually convince everyone.

It's an eventually sort-of-consistent system with a lot of buffering and delay.

if enough people agree that a law should be passed, and it's a high enough priority, and the opinion stays that way for a long time, then eventually enough politicians get on board by virtue of pressure from their voting base, and a law gets passed.

It's not great.

But on the other hand, near-immediate direct democracy is also not great, because it leads to knee-jerk reactions causing laws put in place. I'm thinking of stuff like the USAPATRIOT Act, except worse.