All good points. There is probably not a single solution to the turnout issues. RMJC (SW07) is faced with similar Concours issues, but recognizes that there is a Jaguar contingency that is devoted to the national uniform sanctioning Concours program as a means of national recognition and personal satisfaction.
There are several non-JCNA shows in our area (Colorado) that draw more Jaguars than our club's sanctioned concours. Most of these are "fun" events but some also include provisions for judged or not judged entries at the discretion of the owners. In the interest of supporting the Jaguar image and presenting Jaguars to the public, participation in these events as a regular practice and offering club sponsored open marque car shows and events can help generate interest and participation in club membership.