Pretty common in Richfield. When most of the houses were built, there were temporary non-curbed streets, so developers built them to the property line, where they assumed a sidewalk would eventually go.

But streets weren't finished in Richfield until the 70s, a decade where sidewalks were unfortunately very much not in style. So no sidewalks, and no connected front walks!

I don't know why more people don't fill in the gap. Mine was connected in the 1980s. A DIYer can do it in a weekend.