Cities:

As most cities were founded on thriving farming villages somewhere in there is some remnants of farmland!

Mostly a single family needs 10 acres/5 hectares of useable land to thrive!
In cities the land is still there but in most cases will need rehabilitation or whatever to return it to production!!

Just looking at history most old villages did not just rely on time alone to demolish them, building materials were salvaged/burnt etc
walls were taken down and foundations covered with soil to return the land to production!
Anything interfering with your ploughing was dug up and removed or covered deeper!
A millennia worth of peasant farmers would destroy most ruins!
Same would happen again!
London was prime land at one time! flat, fertile, riverflats, plenty of rain and reasonable drainage to start with!
Could be made that way again over time and effort! Depends if survivors want to work it and the amount of contamination!

100yrs AFTER a collapse there maybe a new smaller London built on the rubble of the old London, it maybe the thriving
hub of a new trading empire with wooden sailing ships going to and fro!
Or maybe just a stinking bog! with the thames blocked by silt backed up around rusting hulks of ships and raising the river level by just a few meters
but permanently until the dam bursts!

 

Here in the USSA:

"LA Mayor pleads for wealthy to help buy housing for the homeless: 'Unprecedented partnership' "

https://www.foxnews.com/media/la-ma...uy-housing-homeless-unprecedented-partnership

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Los Angeles Mayor Karen Bass pleaded with "the most fortunate" to help fund housing for the homeless as part of a new strategy to tackle the crisis during her State of the City address on Monday.

"We will not hide people but what we will do is house people," the Democratic leader touted as she began her remarks on the city's struggle to house over 40,000 homeless people. "The crisis on our streets is nothing less than a disaster."

Acknowledging the costliness of this endeavor, Bass asked the wealthy to help "speed up" housing purchases for the homeless.

The homeless crisis has affected everyone in the city, Bass said, driving away businesses and customers, costing taxpayers city resources and creating safety issues.

"I will just not accept this and our city can't afford to accept it," she argued.

According to the Los Angeles Homeless Services Authority (LAHSA), the city's leading centralized hub for homeless services, more than 75,500 people were considered homeless in 2023, a 9% increase countywide. In the city, about 46,200 were considered homeless, a 10% increase from the previous year.

Fox News Digital reported that a coalition of business owners and residents in L.A. filed a lawsuit against the city, arguing it did not honor its 2020 settlement agreement that promised it would build thousands of shelters and sweep out homeless encampments.

End quote