Wow! Do you have a sense why it's not a profitable business for them? Just on the face of it, they have they have what is arguably the dominant product in this category, and they charge a reasonable license fee to use it.

I find it worrying if "make good software and sell it to people" isn't sufficient to have a profitable business.

And of course, Unity doesn't merely sell licenses, they also run an asset store and take a cut from every transaction, a business model that has been gold for other technology companies. Of course the market for Unity assets is smaller than mobile apps, but this is in addition to actual Unity licenses.