A lot of smaller cities (including the one I live in) are addressing this by designating "activity centers" where new, denser housing is incentivized and sought to be concentrated. Zoning is changed so that, as things like aging strip malls are replaced, a new street grid is laid down over old superblocks.
There's only so much that planning and zoning can do (developers will only build and lenders will only lend for what's deemed profitable), and fully building out these neighborhoods will take decades. But lots of people are thinking about this and seeking ways to make it work. Municipalities have an incentive to get it right. Maintaining the tax base relies on attracting new residents, many of whom are seeking walkable urban(ish) neighborhoods.
There's only so much that planning and zoning can do (developers will only build and lenders will only lend for what's deemed profitable), and fully building out these neighborhoods will take decades. But lots of people are thinking about this and seeking ways to make it work. Municipalities have an incentive to get it right. Maintaining the tax base relies on attracting new residents, many of whom are seeking walkable urban(ish) neighborhoods.