Yes it is as easy as just walking up there, spending a few days prepping a jump and in run, waiting for the perfect dusting of new snow, re-prepping the in-run and jump...then all thats left is just one of skiings most dangerous natural jumps...which btw is in a huge avy path
Now for the reality....Odds are if the snow is good the jump and in run has been built by someone more "important" than you. While there is no ownership, general localism like surfing applies, and if you did not build it, you cannot jump it....so you have to wait till it is bombed out or the snow sucks (either way its gonna be far more dangerous to get sloppy seconds).
That "crew" who built it will not be very "kind" to you, and you will likely be turned around
My analogy is this, I surf nor-cal A LOT, 80+ days a year, I think of myself as better than average and can handle myself at many localised breaks. Last winter I traveled to Hawaii for a sweet winter swell, pipe was hitting second reef at 8-foot (double over head+)...I paddled out and while the surf was within my ability, I would have paddled to shore with a busted nose if I tried to snag a set wave from the local crew. I was left with shit waves and was greeted by bad attitudes. I had way more fun the next day at a less popular and less challenging area...
there are plenty of places to build big jumps....work your way up