because all they do is cause the common cold. They don't cause pneumonia. The flu virus can cause pneumonia, and we pay a lot of attention to it. The experts study it in order to try to estimate what strains of the flu virus will be active so that vaccines can be developed. A lot of time, effort and money goes in to trying to stop large-scale flu outbreaks so that we don't have to order people to stay at home.

There are hundreds of coronaviruses, but most of them are found in animals. Only 7 of them have been found in humans - the 4 that cause the common colds and 3 that have spilled over from their usual animal host to humans. Those 3 are the ones that caused SARS, MERS and COVID-19. it isn't accurate to say we "haven't paid attention to" these other viruses. Because of the research done on the SARS and MERS viruses, we've been able to understand the COVID-19 virus a lot quicker which has allowed the development of tests and will hopefully allow the development of a treatment and/or vaccine very quickly.