The Sears Tower is now the Willis Tower.
At least for the tenant, who is the new owner of the naming rights.
36 years after its completion, what was the tallest building of the world until the late 1990ies and still is the tallest building of the USA, it was re-branded.
Brands are to a large extent what the people think and make of it. Maybe future generations will stop calling it Sears Tower. But the internet makes that less likely today. The global memory searched through Google has some 2,190,000 hits for “Sears Tower”.
Another prominent re-named building is proof.
Ask a New Yorker for the PanAm Building. They will direct you correctly. All though, for 28 years already its official name is MetLife Building. And here too the internet keeps the memory alife. Google has about 52,400 hits for “MetLife Building”, and still 11,000 hits for “PanAm building”.
PanAm is out of business since 1991 and there is little communication about this brand. Sears on the other hand is supporting its brand with multi-million Dollar budgets every year. This brand is not likely to go away like PanAm did.
If the new tenant of the Sears Tower stays in business long enough and sees the naming rights as a real long term investment, it was a good decision. Some decades from now, perhaps people will call it Willis Tower.