I've never understood the need for a sport to legitimize itself as a "real", professional sport. Yet, if not the natural evolution of things, it's the most likely evolution when people are looking to "sell" and profit from the sport. I saw ultimate frisbee go through a similar process starting 8-10 years ago, though those attempts were likely merely the most recent attempts to make this professionalizing move for that sport. Part of such attempts is the need to capture new audiences, with those audiences coming from sports orientations other than the sport that is trying to professionalize. If the right people are captured and the money follows, then different models for the sport, including how to handle round cancellations, could be designed.
But, for now, a cancellation model that doesn't allow for Sunday or Monday play is where the sport is at. And that should be fine. The same could be said for the lack of cuts. An event like GBO is as much about if not more so about the massses than the elite. There's nothing wrong with a model of "we play whether permitting in the time permitting" except it doesn't fit a narrative that professional sports have to be played to completion, especially the big events.
When ultimate frisbee went "legit," they did away with self-officiating to a large degree. To be legit, the game needed referees like other sports had. You could come up with a whole list of criteria for professional sports and "make-up provisions" would be one.
It's worth noting that baseball has bought into a narrative that its professional appeal is suspect, so it is considering all kinds of ideas to make the game more appealing in the marketplace. People argue all the time if pro disc golfers actually move the needle on disc sales; at some level, professional disc golf exists to move discs and baskets and clothing and speciality gear that is becoming more and more specialized. Courses and coverage are also improving and becoming more specialized, but the sport, as a professional sport, is still in its infancy.
Edit to add: Attention to "statistics" also falls under the umbrella of criteria necessary for a sport to be professional. The disc golf stats do nothing for me, but that's because 1) I have other data sports I like such as baseball and 2) I don't watch disc golf caring about the stats.