Reminds me a bit of this:

Unfortunately, out there in the world, its often based on what people can use you for. Our society and industry has been around for such a long time that working positions have become increasingly specialised and different from each-other. You don't need to go to some big office or lab to notice this, look at a construction site. You have someone laying pipes, someone digging ditches, hell, you even have someone holding that "stop" sign.
It'd be very rare to work across two separate disciplines, unless the discipline made sense combined in itself. For example, you'd be hard-pressed to find a direct use for commerce
and say engineering, as taught at uni. You have answers like "well, commerce might help you if you want to open your own engineering practice", yeah maybe but that wont use 90% of the stuff you learned about derivatives and GDP and whatever else.
An example where it makes sense (and its an actual job/position/useful to someone) is something like health economics. You need to know a bit about medicine distribution and the pharmacy system (more policy/law type thing though, wont use much science knowledge) and economics. You work on things like the PBS or for drug companies and figure out if a drug is cost effective. These roles are usually very specialised and in the case of health economics anyway, require a separate masters degree
in health economic.
Don't let it put you off doing it though. University isn't a job factory, its also a place to learn (surprise!). These are some of the best and most free years of your life, soak it up. If it takes you an extra year or two to do it, so what if it makes you happy? Personally, i like being in uni anyway. A few years really, really, really is nothing. It might seem like a lot but it isn't. A lot of people fail subjects/change degrees/swap subjects/take time off/go on exchange and dont finish their degree in the alloted time anyway.