I think the intent is, like patents, to prevent someone else from undercutting your price and reaping reward for your investment in innovation but at the same time saying if you make a significant contribution to the greater good then you can immediately apply it to the current state of the art.

You can benefit from our innovation but only if it's in addition to your own innovation.

I kind of like that because unlike patents which stifle innovation, it encourages acceleration of innovation.

Patents encourage publication of inventions, either as part of an application for a patent or as a defensive publication to prevent others from getting a patent. They allow (UK, not sure about other jurisdictions) research, can always be licensed. So is it just the monopoly length that is stifling?

The main alternative regime seems to be industrial secrets, are they less stifling?

Industrial secrets might be less stifling, because reverse engineering is usually faster than waiting 20 years for a patent to expire.

Then of course there is the option of embracing open source across industry by recognizing as a culture that widespread innovation grows the economy faster than restricted innovation.

You can buy Prusa MK3 kits from Aliexpress for half the price of the original. I bought a kit from Prusa and one knockoff from Aliexpress. Parts wise they are 100% the same and perform the exact same way. Do I feel bad about it? Kind of. The Chinese seller certainly did not put R&D into any of it. And being in China makes sourcing much easier.

Yeah, I've bought a knockoff on Aliexpress too, but mine was not a 100% clone. I bought a kit that came with the Bear upgrade and didn't come with the parts that would be replaced during the Bear upgrade. Those are the ones I think are hard to define without being vague. My worry is that by adding vague and all-encompassing restrictions, the license will no longer be free.