Your post is interesting. There was a Veronica Mars theatrical film that was financed by Kickstarter. Reports in the press indicate that it was a minor success - with a box office of about $3 million on the weekend of its theatrical release.
Yes, David Rasche is now about 70 years old, so it would be tough to retain the original cast. But he looks much younger, so he is still somewhat viable.
Kickstarter doesn't seem to be used much to get films started, mainly because not much money is raised by that method, and because there have been no big successes with Kickstarter films.
Alan Spencer has many options with regard to Sledge Hammer! Cable networks do original movies, as do the major networks. But the biggest thing in his favor is the great quality of his creations - all of which have shown wit, intelligence, and delightful humor.