At this point, I'd settle for taking the 2-lane road segments in my town that turn into 4-lane nightmares and then merge back into 2-lane streets a dozen blocks later with bike lanes and parking, and getting rid of the 4-lane parts that often don't have sidewalks or bike infra.

Sure, these road segments funnel traffic away from the more-residential city grid streets, but they're also rife with speeding and they make it hard to navigate on a bike unless you happen to know which streets have any sort of infra

To take this to its logical conclusion, once the streets are gone, there is no need for buildings anymore, so they can tear those all down and plant a forest. But then you wonder where you are going to put all the people who used to live and work there.

Eh, keep some for emergency & delivery vehicles, public transport and bicycles.

I think the ideal is an alternating block structure

Pedestrian Street,

Road,

Pedestrian Street,

Transit only Lane,

Pedestrian Street,

Road,

Pedestrian Street,

Transit Only Lane,

...

Where Pedestrian streets cross roads, have car traffic enter a roundabout sunk below the pedestrian path, when they cross transit lanes, have a gate bridge that closes off the lane whenever a tram or bus isn't near the crossing, same deal when car traffic crosses a tram or bus lane

Voila, maximum restriction of cross interaction between three separate modes of transport, a full 75% of which is dedicated to pedestrian and transit use, and the last quarter there mostly just for the benefit of last mile package delivery and emergency services, as well as the odd profession that legit has to use automobile transport for whatever reason.