This particular experiment may not have turned out as hoped, but I believe it's too soon for the concept to be written off.
And an experiment is what it should be regarded as.
First prototypes, of almost anything, seldom end up as the final design.
The solar generating road surfaces described here are clearly not yet sufficiently efficient or hard-wearing - so they need to be re-engineered. If the driving surface needs to be made quieter in its interaction with vehicle tyres, then that can be done, given faith and investment. Clearly, some of that investment will have to be in the form of venture capital from State sources. And yes, it does have to be acknowledged that venture capital sometimes doesn't come back.
But a road that might start out being able to only generate enough power from the sun to run its own street lights and interactive cats' eyes, might one day be able to generate enough power to supply an induction feed to top up electric vehicles driving on it. And while we're about it, there's no reason why the poles on which said street lighting is mounted, can't also accommodate wind turbines.
These kinds of ideas are where we need to be looking into the future, even if at first they don't succeed.