I had a conversation with my brother and his friend who had come to help work some locks today. One had heard about the C&RT funding issue. Both said canals were a great resource for the community, walkers, bikers etc. and talked about the heritage. I menoned, unlike charities like Natoonal Trust and English Heritage most people don't pay to access it. The problem with C&RT fundraisers canalside is at least two-fold. 1. You don't need to pay. 2. Cancer, heart, dogs charities etc are much more high profile and more likely to have a personal pull for any spare cash you might have and want to donate regularly.
How many people have such an affinity with the canal heritage, landscape and amenities they want to set up a direct debit to support C&RT, before other causes. I guess most boaters already feel they pay enough already and wouldn't want to contribute more.
Its not easy (possible) to fill that gap through community fundraising.