duncan: new census data shows america s largest city saw their sharpest population losses during the pandemic. well, it turns out they re rebounding, and fast. here s cbs michael george. reporter: if you were mourning the decline of san francisco, you can probably dry your tears, the city is booming. we came here to be around other, like our friends. reporter: startup founder kunal gupta and joe ahearn just moved in and say for them it was a no-brainer. san francisco is the startup capitol of the world. and even though people have been leaving san francisco, we have no doubt that that continues to be true. reporter: millions left cities in 2020 during pandemic shutdowns, heading for the suburbs and beyond. but now many are returning; real estate markets are skyrocketing. restaurants are packed. and even traffic is back. we now see an urban revival. the beginnings of an urban revival. reporter: university of
toronto professor richard florida is studying the resurgence of america s major cities. he says many people who left just moved a few hours away. one of the things i think that s changing our cities is, cities are going to be less about a place to go to work and much more about a place to go connect. reporter: this spring in manhattan real estate brokers report the number of sales surging to the highest level in six years. howard lorber of douglas eliman realty. everyone saying, isn t new york city dead, isn t new york city dead? , and my answer was no, it s not dead. it s in a coma. but people and cities come out of comas. hopefully. reporter: office vacancies are still high and cities are dealing with challenges like crime and affordability. but for joe and kunal they found something in san francisco they say they can t get anywhere else. the value of any city is the sort of spontaneous connections that you can have living in t it