Yes - it was a mistake to close Colne - Skipton, but now can we justify the cost of reopening ?
Skipton is not a huge town, and the preferred destinations for local residents are probably Bradford & Leeds rather than Burnley, Blackburn or Manchester. I doubt that there would be enough regular / commuter traffic to support a railway.
Between Colne & Skipton, the only largish settlement is Barnoldswick - not served by the direct rail route, and too small to justify reopening the branch to/from Earby - and Earby itself is too small to generate a lot of passenger traffic.
Burnley already has trains to Bradford, Leeds & Manchester, no advantage to people going via Skipton instead. Colne & Nelson are probably not large enough to generate large numbers of regular travellers to Skipton & beyond. Occasional surges of passengers visiting Skipton Market will not support the cost of a railway. As posted above, a semi-fast service from Colne/Burnley would be a worthwhile improvement, but possibly going to Bolton & Manchester rather than Preston or Blackpool.
Freight ? What freight ? Since the end of coal mining and closure of power stations, there is no freight originating in the Burnley / Colne area. About the only regular freight in the area is the Lindsey/Preston tanks, typically once or twice a week, and adequately served by the Copy Pit route.
Freight traffic through Blackburn to the north is adequately served by the Hellifield line - and in any case has declined due to loss of coal traffic to power stations. So I fear it will be very difficult to get money to reopen Colne - Skipton.