I feel like this is an annual thread, normally around this time of year too, it will be okay, five months till the hill opens.
1. NJ is one of the most densely populated States in the Country, that being said if something gets built, it gets noticed. We also live in a very sue-happy culture. These two combined lead to some pretty serious issues that have closed parks, both sanctioned and unsanctioned. Hence to the destruction of trail features by land managers to avoid being sued or a number of complaints from non riders.
2. I hear ya on the other State issue, but some of the areas we see some of the best big hit stuff built in are out in the middle of nowhere. The people that at hitting the feature (pro athletes) often have insurance for injuries associated with these features. features are usually demoslished after being hit or grow in, as reality states there isn't a line of people waiting to take down a 50 foot gap.
Large areas are also covered under an "attractive nuisance" policy, so if something is built on a large swath of land (although it is usually owned by the government) the law understands there is no way a landowner could police the property for man-made danger he or she did not create, and is therefore exempt from suit (sort of). In NJ this is not the case, things are often spotted, but in reality most builders here don't always use their brain and place features on multi use trails. Let’s face it, you do not see the big names in freeride building hits on a multi-use trail.
Most stuff that is built here is kept quiet, because once the word is out everyone rides it/posts pictures, the land manager comes and destroys it.
Also, let’s not forget, a lot of trails are destroyed annually, as they are pirate trails. The more notable places like the North Shore have only gotten to the point where large donation and volunteer bases have been able to sustain some trails (also helps that on the Shore and Moab these are huge income sources from travelers). With these donations insurance is purchased. But we do not have the same base size of riders willing to donate or do work, and many are not patient for the slow change.
Heck.....Jorba only has 300 members.....there are many more dedicated riders than that.
Most sanctioned trail work events only have a few people show up, which are there to fix & repair work, let alone build stunts solely used by the cycling community (not enough man power or time).
Want these features, Join Jorba, donate, and give your time. Don't build illegal trails in santioned parts, in the long run it hurts what you are trying to accomplish.
Enough from me, there are bigger chiefs that can provide more info.