I understand your sentiment.
However where I live and at the times I'm free, the roads are busy and the paths are not.
On a sunny weekend day it is likely to be the opposite, where your point stands.
We could also use these routes post-lockdown, so I will be continuing the thread.
As we're meant to be avoiding coming close to other people, narrow paths that are likely to be popular with walkers and joggers seem a bad idea.
There's plenty of wide open roads with virtually zero traffic. The West End and the City especially are mostly empty.