New powers are different

This, via Radley Balko strikes me as a hugely insightful point.

It was easier for Obama to fire the CEO of a private company than it is to fire most federal employees.

Corporatism doesn't just lead to massive inefficiency in the economy and cause a dangerous increase in state power. On top of those problems, it also changes the balance of power within the government. As observed, the president has more personal power over a newly semi-nationalised company than he does over a government agency.

Existing state powers get fossilised into the permanent (civil service) structure, largely out of the control of the executive. When new powers are acquired, they are normally under much more direct "democratic" control than old powers. Over time, as the consequence of the powers being used "politically" or even (gasp!) by a "populist", they are taken over by the permanent establishment.

In this country, we have seen it most clearly in relation to the E.U. Something that would be very difficult for a politician to do directly is much easier for the same politician to do by proposing it to the European Commission and running it through as a directive.

This could be a major reason for the steady drive for more state power. It is not that politicians think the government doesn't have enough power, it is that they need the government to have new power that they can actually control.