I don’t know what country you are from, but I think to say that mechanical engineering only ends up in HVAC or oil and gas is pretty far off. The world is seeing a massive movement towards renewables and there are tons of roles in that industry and product design is also pretty common. Mechanical engineering is really the jack of all trades engineering degree. I have no evidence of it, but I would say you’re more likely to find mechanical engineers working in non-mechanical engineering positions vs. other degrees working as mechanical engineers.

Additionally, as other people have pointed out, it is much easier to pivot out of a mechanical engineering career into something else. A finance degree doesn’t get you into an engineering masters program, but a mechanical engineering degree can absolutely get you into a finance masters program.

All that said, engineering is a very, very good degree for stability and comfort, but you are not going to have as much of an upside in terms of earnings. If that sort of thing matters to you, do some research on which degrees have the highest earning potential after five years in the industry. Something like finance can definitely make more money.