IIRC there are ways to use the firmware blobs with the official free ISOs, but I have never bothered with that, just having them present in the ISO and not having to fiddle around with putting them where they are expected is easier.
You can just add the firmware.zip file (or extract it, I don't remember clearly) to a USB drive, and the installer will just mount and use it during installation. So, if there's a tool to merge both easier, or better documentation for the current situation, the problem will solve itself, in my opinion.
The blog post is putting the idea of adding the firmware blobs into the official ISO files, and as a Debian user, I'm not comfortable with that.
So, I'm offering another trade-off: "Make inclusion of firmware blobs to installation media on the fly easier, keep firmware off the official ISOs". It's a bit of a DIY solution, but it doesn't need flexing policies, DFSG and the values Debian is standing for.
It's a thin but important line to cross for me.