Ya I think this is likely true, but we always kind of knew this, some or even many people were not being diagnosed thus the fatality rate was lower, perhaps significantly, then what the recorded data is saying.
However the fatality rate is not, imo, the main indicator as to how dangerous this thing is. That is because this thing is so contagious, thus many more people will catch this then the flu. So even if the fatality rates are exactly the same Covid will kill many more people, because so many more people will get it.
Then you have to consider the tolls it is taking on Hospitals, we've seen it in NY, we've seen in NJ, and now we are seeing it in other states around the country like AZ, NC and TX.
The fatality rate is a small consideration in discussing how dangerous this virus is.