I think the discussion is a lot more complex than footpaths.
Not all public footpaths would be suitable for cycling, although a great many are, however there are also thousands of miles of trails, everything from made up access roads downwards, that remain out of bounds to riders on access and common land, where walkers (and horseriders in the case of many commons) have an unrestricted right of access.
If you read the joint CTC/BC/WC/OpenMTB response to the Welsh Government access consultation via here then it will show some of these arguments in greater detail (results due soon, but we know that cyclist ended up being the biggest response group by far, making this the most successful consultation the WG has run)
The success of #TrailsforWales and the rebranding of CTC as CyclingUK next week has the potential that they will be giving more effort to MTB access issues in the future (working with others) hopefully we can all get behind this.