That’s the « they ». Everybody in the fifth republic believes that the state should regulate the economy, while having absolutely no personnal experience in the private sector. The only differences they have are on society issues, but from the economical point of view i have yet to witness one government that actually lowered the tax ratio ( just look at the CSG which was supposed to be temporary and 3% 25 years ago, and is now still alive and reaches more than 10%)
As for the efficiency of the public sector and the tax system look at france’s tax vs gdp ratio compared to other european country, as well as our ranking in education performance ( both young children school and university). Also have a look at unemployment rates, compared to other european countries.
Edit : to be fair, macron did come from the private sector ( just a few years though), and he did in fact remove a huge chunk of the ISF last year. That was a glimmer of hope. Also another reason why seeing France go back to its old habits makes me mad.
2 - I know a capitalist system that notoriously fails to redistribute wealth even though it's the richest economy in the world. Its ruling class seems to be keen on implementing those ultraliberal taxation ideas of yours. Sub-par healthcare and expensive education is the result. Then again, that is not a system that I think is worth emulating.
3 - As much as I appreciate politicians in general, I wouldn't be so immodest as to pretend that they're a bunch of stupid bureaucrats, meaning by that that I know how things work better than they do.