I'll put this as nicely and un-inflammatorily as possible. Hartshorne is built on the site of an old military installation (which is probably also the only reason it's a park instead of 5 really expensive houses); Huber, including the house, were a gift of the Huber family, who still live in the area. I remember very little from my childhood, except that for the trails that exist now, where you see chutes, or deep cuts, used to be at the level of the top of the cut. The erosion in the parks is not absurd for the area, but a critical lack of maintenance, cleaning, and repair/rerouting of trails are contributing factors. Particularly bad trails are built on fall lines. Compared to parks like Sterling/Wayway/Ringwood up north, and Allaire farther down, Hartshorne and Huber receive only basic maintenance (clearing downed trees, intermittent trimming). Some of this is due to a lack of people, some of it due to a lack of extra volunteers (MoCo only allows supervised volunteers, and only as scheduled, once a week, spread out over ~10 other trail systems), some of it due to the leadership of the county park system, and some due to employees. I would be remiss if I didn't point out here that there is a contingent of people on bikes that don't believe closed trails apply to them (see: Laurel Ridge switchback with the horribly eroded hillside, and other straight up closed off trails).
The trails themselves have fared fairly well, except for possibly the worst offending trail in the park: the climbs--in either direction--out of Buttermilk Valley, and in the last year, the switchback descent in Rocky Point. You can make of the attempts to fix Buttermilk Valley whatever you will.
If you want to get involved, contact the county volunteer system. If you want to get even more involved, contact Jorba.