The airspace may not be, but defined airways can be, as well as controlled space. Airliners have had near misses. GA guys with their heads up their ass, anything can happen. Don't underestimate stupidity and lack of watchfulness.
I wouldn't completely rule out foul play, but in my personal experience, (responding to emergencies) I made very few calls on motorcycle wrecks on rainy days or in heavy traffic. People are far more attentive in those conditions. It was most often an unforced error on a beautiful day. There's also the possibility Harrison Ford was one of the pilots.
Oh yes Alaskan air is very crowded!
“The state is home to 403 public-use general aviation airports, more than 5,700 active GA aircraft, and over 8,000 active pilots. Alaska has more private planes per capita than any other state and Alaskans fly more than eight times as often as citizens of other states.”