As anecdata, when I graduated from grad school in the mid-eighties, other than Manhattan financial people, pretty much no one I knew went to live in a major city. In Massachusetts, none of the computer industry jobs were in Boston any lony longer.
A lot of it was bad luck. Sears shut down their catalog operation in 1993, because it was losing money, but if they'd held on for a few more years they'd have been in a prime position to be Amazon.
I did shop at Sears at one point especially after I bought a house but they became increasingly uninteresting relative to alternatives.
They had had a catalog operation and by some accounts class-leading (for the time) information systems. They had Prodigy and more or less successfully pivoted into making Prodigy an ISP. Undoubtedly they knew a lot of things Amazon had to figure out from scratch. The notion that Amazon was a great invention rather than just great execution is kind of risible.
Flip it around - what could Amazon have done with 1500 marginally profitable retail stores and a storied brand name? Sears kept the party going for a couple decades after the dotcom era, and still exists, so they weren't on the brink of folding back then. Note also that Sears' failure was not preordained: other brick-and-mortar retailers from the era have survived and even prospered.
I think it's an open question what happens to downtowns with the diminution of brick & mortar retail and people coming into offices (even if the latter has reversed in favor of office work more than some had predicted). A lot of cities have ebbed and flowed over time and there's no guarantee of a specific universal future pattern whatever some individuals may wish for.