So it's completely preventing flu while COVID is out of control?
Measles is 3 times more contagious than Covid. The flu is much less contagious and the measures used to keep covid at bay are sufficient to all but eradicate the flu.
The differences are for more than one reason, the amount of replicating virus particles the carrier is shedding is different, the virus particles can survive more/less after being released, the viral load required for the virus to take root in somebody is different, the time period when the carrier is shedding can be shorter/longer, and even the amount of carriers who are shedding infectious virus particles isn't always 100%
That's how the UK variant can be more contagious than previous strains.
There is a big misconception that all of the social distancing, sanitizing etc is completely ineffective. In 1918 50m people died from a similar pandemic. We are still under 2m. The current mitigation strategies are wildly successful.
All I know is that flu was always a seasonal illness and only went around during specific months while COVID seems to be year round. However, during the months that flu did spread, which usually peaked in January and February (as per my pediatrician) it was very contagious and there were millions of cases (according to CDC in 2018-2019 season there were 35.5 million cases in the USA).
It was more contagious then without measures. Covid with measures is R3-4 which would have been much more than 35m cases.