Who decides that the IRS shouldn't have a free filing system and Intuit/TurboTax should be able to rent-seek on the country? Who decides that megachurches are a-okay and tax exempt? Who decides that hairdressers need a license?

Sure, money is always involved, "political capital" is real, but accumulating more of it doesn't increase the capacity of global political system (as economic capital grows the economic capacity), it just consolidates and polarizes it. So fucks it up basically. And in that regard it's more like a market failure of politics. Too little political competition, too much outside influences and forcing factors. (Eg too much ideology. Or a kind of cross-financing props up one side - basically somewhere in the decision making hierarchy that small sector was conceded, sacrificed, so Intuit continues to make big profits, but something else happened instead, let's say some state got some subsidy.)

All in all, first-past-the-post voting entrenches the big power brokers. (Who might not be the elected officials, but quite usually of course are.) Then the emergent two-party system leads to polarization of other issues. Local issues also became party issues. This brings some uniformity and consistency, but obviously does cause a lot of inefficiencies too.

So, how does it benefit them to do X? Probably it makes them good party members. And that consistency makes the party viable long term. Thus even local changes can only happen if the whole country zeitgeist changes.