multifoliaterose:

What evidence do you have to support this claim?

To answer your question fully, I would have to expound my entire theory of the modern state, which would unfortunately require much more time and space than can be dedicated to a blog comment. So what I write will be very cursory, simplified, and incomplete.

The basic insight is that elected politicians are transitory and in constant danger of having their careers destroyed by bad PR, while the bureaucrats are entrenched like the rock of Gibraltar, constantly running circles around politicians and preventing them from doing anything that deviates significantly from the direction in which things are carried by the bureaucratic inertia. Politicians lack any means to dislodge the bureaucrats, who can in turn make their life miserable in many different ways. In case there's a direct conflict, the politician loses without exception. The only sensible strategy, which successful politicians inevitably follow, is to simply give up any thought of such conflict.

Of course, the bureaucrats won't mind if politicians do things that create more bureaucracy, but even in that case, the actual consequences of such measures are principally in the hands of bureaucrats, not politicians. Legislation is nowadays typically written in a long-winded and extremely vague style, leaving it up to the bureaucracy and to some extent the judiciary to shape it into actual policy.

This simple view omits the crucial roles played by the judiciary and by various other centers of non-elective power whose social, organizational, and financial structure effectively blends into the government even though they're theoretically not part of it, such as the mainstream media, academia, and various for-profit and non-profit nominally private institutions. However, these merely present additional limitations to the power and influence of elected politicians, and they typically operate in concert with the bureaucrats, giving them some of their crucial leverage against politicians. It also ignores some (mostly vestigial) limited ways in which politicians can sometimes exert direct control over things.

On the whole, this is an immensely complex and controversial topic. However, any plan for influencing things by electing politicians must recognize this state of affairs, or otherwise it completely loses touch with reality.