Red Hat Announces Broad Expansion to Open Source Patent Promise

They already have, its called the open invention network, which uses similar theories iirc.

One difference between the RH patent promise and the DPL is that the patent promise only extends to open source/free software, released under a license recognized by either OSI or the FSF. Would that be possible with a license?

But maybe it's just a historical reason.

The above website shows the most recent patent having been added in 2014. Why the poor uptake?

I wonder how the DPL is compared to the MS-PL which is more BSD-like and does mention what happens if someone makes a patent claim against the code, they basically forfeit the right to using any of the authors own patented code / solutions, ie the entire code base probably becomes useless legally speaking.

https://opensource.org/licenses/MS-PL

I always found it silly when some projects with patents dual license as BSD and one other odd license, and depending on usage of code they relicense it when there's already licenses like the MS-PL. That's just my opinion anyway, what do I know, I'm not a lawyer. I just stay away from weirdly licensed projects though.