And also cannot be used in open-source projects.

CC-BY-NC amounts to saying: you can play around with this in demos and academic projects that no lawyer would ever go after anyway, but you can't use it for real.

Is that entirely a bad thing? If a commercial, for profit wants to enter this field then they can pay for it or licence it?

And what if an open source project wants to enter this field?

For open source commercial, it's the same as for-profit. They'll probably get a discount.

For open source non-profit, it'd still be NC and therefore legal?

"Non-profit" is a whole different kettle of fish than "non-commercial". It doesn't mean you're not selling anything. It doesn't mean you're morally good. It just means you registered for a particular business status with particular restrictions. And it's not what CC is talking about.

A key part of the Open Source Definition is that you do not lose your permission to use and copy the code based on what you do with it. A project that you aren't allowed to use anymore if you start making money from it is not Open Source.

"Non-commercial" code restrictions are more like the thing where you're allowed to look at the Windows source code, if you're an academic and you ask nicely and you won't ever do anything with it.

A lot of universities are open to give a separate commercial license when contacted. They charge for their efforts, which is fair. Whether public universities should charge given we already pay them from our taxes is a different issue. source: I am also cofounder at an AI startup, we often buy licenses to use academic datasets for commercial usage.