Dedicated activists are kind of rare as politicians. I can think of a few but not many, and they normally become politicians precisely because they're fighting for a popular cause that mainstream elites are suppressing.
So yeah, they want power and status because they are humans. They join party X as opposed to party Y because that's their preferred direction.
I was saying that it's more common for ideology to be an afterthought for most high level politicians rather than the primary reason (as you previously asserted) they get into politics.
You'd expect that it would mean less intransigence about policy in the face of democratic pressures, but it doesnt. Probably because money is the real driver.
I personally know one politician who was part of a mainstream party politics for years and his ideology was... fluid at best. He ran for election and lost and was almost immediately shunted into a safe, well paid job at a corporate NGO where he rabbits on about sustainable investment.
After digging into the personal stories of many other people in this "left" party I realized that his story was completely normal. The candidate in my area was a black woman pulled from a public relations company linked to the party elites. She speaks with the veneer of ideology (vaguely and on "safe" topics) but it's obvious that it's ambition that drove her.
If I decide to join the X party as opposed to the Y party, this is supposedly because my mind is already set, and X policies align more with my set of preferences than Y policies.
Failure to listen and adapt, if anything, tells more about how Western politicians are increasingly worse at being politicians, (i.e. at achieving tangible policy goals evaluated according to their own set of preferences).