It is in large because of the virus: the reduction in demand for flights made the 747 the prime target for retirement.
Without a pandemic they would have been replaced gradually by newer planes, now they are just sitting unused so they are sold and scrapped.
The phase-out of the 747 was well on the way long before the pandemic was ever a twinkle in a pangolin's eye, or wherever it came from. Those airlines that still fly them are mostly not changing their plans to either phase them out or keep flying them due to the pandemic.
As at the end of 2019, there was not a single scheduled passenger operator of the 747 anywhere in the Americas, and only two in Europe (BA and Lufthansa). Prior to the pandemic, BA announced plans to retire all 747s in 2024. They brought forward the date due to the downturn, but they're the only airline to do so for their 747 fleet as far as I can tell. Lufthansa flies the new 747-8 and is very unlikely to retire them any time soon.
There are still plenty of 747 operators in Asia: among others, Air China, Air India, Thai, Rossiya, Korean, China Airlines. Thai and China Airlines both had existing plans before the pandemic to retire their aging 747s, and the rest have all indicated that they plan to keep flying them.