Sunfish,
I guess we are going to have to agree to disagree.
You are not even close as to the DGPS available, and what position accuracy I can get, pretty much anywhere in Australia, RFN.
Tomorrow, from Australian retailers, I can buy now what I regard as quite an amazing range of ready made circuit boards, from a range of manufacturers, some of whom, I am please to say, are Australia, that are not only GPSIII all signals capable, but can simultaneously process Glonass and Galileo signals. They meet their specification, not marketing hype.
Indeed, if I was in the drone commercial business, ( as a good mate if mine is, if you are in NSW, you are benefiting from his airborne infrared fire mapping) from the same sources I can also buy comparable AHRS systems, giving me the core of a complete flight control system. And, if 3m positioning for commercial transport operations is not good enough, these will easily produce 3-4 cm. Amazon parcel delivery??
BUT, ALL THE WAY THROUGH, you are completely missing the point, we all (or most of us) know what SBAS/WAAS can do, some of us know what alternative currently available systems will do, but this "revolution" is ONLY about aviation, and so, I say again: "What is the catch".
Tootle pip!!