If government is actually the top power on the land with oversight over and the power to rule over everything, then the power of voters which choses the people who lead said government controls the top power on the land, which is what’s known as Democracy (even when imperfect).

However if government ties its own hands so that it doesn’t really oversee or rule over the domains were Money has the most power, then it’s not the top power on the land anymore - Money is - and the votes of people do not control the highest power on the land anymore, they only control a secondary power, so what you have in not Democracy anymore, it’s Oligarchy - Money is not democratic since doesn’t have any “one person one vote” rule and instead some have billions of times more power than others.

“Small government” is really just a slogan for a government which has had its hands tied by reducing its funding so that it’s unable to oversee, much less rule over, the areas where Money dominates, especially when it comes to facing the wealthiest people and companies. Mind you this only works if the other elements of Democracy are kept, so Money still wants a Judiciary and Law Enforcement independent of Government to uphold their ownership of things and stop the plebes from taking their shit, just a government weakenned in all other areas and unable to fight Money in the Courts.

And also way more expensive than big government