Because skiers abused the privilege, and I don't have all the details, but the park was like "never again". Ask Rob some day, it was his generation of skiers.
I can't speak for the history. I know going downhill on a bike, without pedaling, I can exceed the posted "speed limit" on the Down Road. Easily.
Interesting. I wonder if enough time has gone by that it's water under a bridge by now. Because apparently for the North Face races they are turning the lifts for spectators, so the lifts are designed for downloading. If it was ever possible you could ski from the ski area to the summit, then take the lift down, and do hill repeats that way. The pavement on those roads looks real nice, and it's closer than Greylock.
(There's also the question of whether the DCR has the authority to unilaterally bar rollerskis from Wachusett, but that's probably the wrong way to go about getting anything changed if we so wanted things to be changed.)
And Sam, I think I'd ski up, and get a ride (or even walk) down.