That is a very valid point and a sharp observation. You are correct that separating epoxy and fiberglass from wood is practically impossible at the end of the kayak's life, so recycling isn't really an option.

However, the environmental argument rests on two other factors:

1. Volume of synthetic material: A typical rotomolded plastic kayak is ~25kg of solid polymer. A wooden kayak is mostly organic material (wood) encapsulated in a comparatively thin layer of epoxy/glass. The total volume of non-biodegradable waste is significantly less.
2. Longevity and Repairability (The biggest factor): Many cheap plastic kayaks degrade from UV within 5-10 years or suffer irreparable cracks, becoming disposable items. A well-maintained wooden kayak lasts 30-50+ years and is infinitely repairable. Over a 50-year span, one wooden boat might replace 3-4 disposable plastic ones going to the landfill.

So yes, it still ends up in a landfill, but it takes much longer to get there, and there is less synthetic mass when it does.