The severity comparison was not opinion but taken from a medical expert in an article on CNN.
Here is a more recent one saying the same. .... also any person with half a brain knows that rate of transmission of an illness isn't the same as severity. The common cold spreads easily and very fast, something like hepatitis does not .....which is more severe ? ..... this point is also made in the article and quoted below.
"So far, experts say, concerns that the Wuhan coronavirus is the next SARS are overblown. The two virus' symptoms and origins may be comparable, but their severity is not.
The new coronavirus appears to be less severe than the SARS, former FDA Commissioner Scott Gottlieb told CNBC on Friday. It might be more contagious, however, given that the outbreak is spreading faster than SARS did"
of course we also know that viruses such as the flu and likely this one tend to mutate and so could become worse. The flu virus changes all the time and thats why the vaccine must be changed annually depending on the strain and its mutations. The flu vaccine is typically made from the last known strain so might not as effective on new strains only the one that it was made for. A difference between the flu and Sars is/ was that we have a vaccine for flu not these other corona viruses.....yet even with vaccines, the flu kills 10's of thousands annually , whereas SARS fortunately only killed less than 1000.
as for a man in his 50's dying ... healthy people die of the flu every day , including people much younger and children. Obviously, They are not the norm but the exception as typically those with compromised immune systems or pre existing conditions, and the elderly are more suseptible.
80'000 people died of the flu in the USA alone in 2017 , some, even many would have been normal healthy people. Unfortunately , some are saying this year could be even worse ....hopefully not. The most troubling thing is the flu death count could even be higher than the figures ....as per the article.