is it possible for some "mining cartel" to have enough mining power to influence any kind of economic or political decision? I'm not talking about "control the network", but more in a form of economic conjuncture.
Imho the history shows it's not possible to make decisions only because "mining cartel" wants them. Do some research on SegWit2x.
Some pools wanted that, quite powerful group, but after all the majority or the network (meaning also nodes, for example, clearly not only miners/pools) decided otherwise.
Bitcoin is about consensus. The majority has to be overwhelming and the network keeps expanding, making such majorities hard (next to impossible) to achieve if the goal is not right.