Which ideas? Like electric cars are a pretty legitimately good alternative to ICE cars. Ofc investing into public transit would be better, but that’s a social problem, not a tech one. Reusable rocketry seems pretty legit. Starlink does seems like it’ll be a massively taxpayer subsidized money black hole, though.
I’d say most of the issues I have with the Elon are his social policies (anti-worker) and views.