It would be great in a city of ~ 275,000 to be able to find a dozen or so people who regularly ride and not have to go through an ordeal to get to the start of a ride (whether its loading up a car, catching PATH/Ferry to get there or riding 12 miles to the start of a ride.)
There are more than a dozen. The thing is, they are all of different levels of ability, different availability, different interests, different schedules. To support a dozen people consistently every Saturday, you'd probably need 50-75 people or more. Plus, people willing to plan rides and lead on a regular basis.
And if it's in JC, as noted, where do you go? Let's face it, Hudson County is not exactly superb cycling territory. I for one wouldn't be thrilled if every group ride, every Saturday, started with the same ride up to Palisades Park or 9W.
Plus, lots of people in bike clubs drive or commute 30+ minutes to the start of a club ride. It's not that big of a deal.