I don't think @So_I_Ski's only argument is that "no one can run 9.75" and I think the idea that any fiddling with line lengths (adding a 10m loop) is futile because (@Horton) "the end result would be the exact same show we have today" nor that (@keithh2oskier) "if nate goes and runs a 10, then we are right back where we started."
There is some nuance here that needs to be teased out.
It's true that there is not an urgent issue right now: no one other than Nate is getting through 10.25 (-41) with any regularity, and most tournaments bunch up around 3@10.25, as they have (increasingly) for several years now. Maybe that will continue to be the case — that every tournament bunches up around 3@10.25 (-41) for the next two or three decades, and the sport doesn't 'progress' much. Personally, I'm still excited anytime someone actually turns 3@10.25 and makes a real attempt at 4, but I suspect it won't be as thrilling (at least for me) if that's still considered a great score in, let's say, 2031 or 2041.
More to the point: if we ever start seeing skiers run 10.25 more often, we have 24 years of evidence that suggests that what comes next (9.75m/-43) won't be that exciting: it seems incredibly difficult to do anything more than 1 @ 9.75 and we could find ourselves stuck there for eons. Maybe I'm wrong, maybe some ski designer makes it easier… I dunno.
To be fair, it's true that other sports' world records can get stuck for a long time and the competition is still (somewhat?) exciting (Track & Field's High Jump has been stuck @ 2.45m since 1993; Pole Vault got stuck for 25 years but last year made a bit of progress).
On the other hand, the rule to go from 10.25 to 9.75m is arbitrary (we could change it if we all agreed!) and if skiers ever start running 10.25 with any regularity, we may regret having decided that 9.75m is the best, next line length. Adding a 10m line length would improve the chances that we might start seeing skiers-not-named-Nate turn 2 or 3 or even 4 ball @ 10m over the next couple of decades.
I could be totally wrong, of course: maybe every few years someone adds a 1/4 ball to the record @9.75m in the coming years. But over the last 24 years, threats to the world record have been few-and-far between, compared to 1980-1997 when the world record was being threatened regularly… a way-more-fun era for the sport, in my books.