No, it's not better to spend limited funds on an assumption when existing needs are not being met. Would you spend your limited dollars to add a sunroom that you assume guests may use, or instead fix the existing hole in the roof?
I pointed out the weakness of my argument. The weakness of your analogy is that many bike infrastructure projects are a part of larger, resurfacing project. If a fire destroyed one wall of my house, I might as well change where the windows were during the rebuild.
For the multi-use paths, I see a lot of walkers, runners, and bicyclists on the paths. I qualify them, especially the Olentangy Bike Path, as worthwhile expenditures of public funds.