why would a government impose limits upon itself? what incentive does a politician have to do so?

take this trump admin, easily the most wildly bullish bitcoin admin thus far. all he says is, you can play with your bitcoins but the dollar is king and he cares about the dollar. the only legislation that will get passed on 'crypto' in his term is stable coin legislation, in order to further solidify the dollars dominance across the globe so we can continue to debase the currency, export our inflation across the globe, and pay off our debt with devalued dollars