Then at different times, both cities were revitalized by development by the water. Boston had Fanueil Hall and Miami had South Beach. Then later it mushroomed from there. Both became desirable places to live, so people were moving back to the cities.
Except lately. Miami has available land, so they kept building and building, whereas Boston is landlocked and really cannot with a few exceptions. Have a look at Pat and several such buildings.
I stopped counting at 47 mostly empty buildings on one street alone. So imagine if you are trying to sell your home. You have lost a ton of value. In Boston, because we could not build, prices have mostly stabilized. Building and remodeling have started to return. Thus we will pull out of the recession/depression/shock early than cities like Vegas, Stockton and Miami.
Sometimes its better to be lucky...