This is exactly right. The most recent data I've seen indicates in those aged 70 to 79 years had an 8% fatality rate and those aged 80 years and older had a fatality rate of 14.8%. There is also increased risk for those with weakened immune systems (cancer patients, HIV, on immune suppressant medication for Lupus, Rheumatoid Arthritis, Ulcerative Colitis, etc) as well as diabetes and cardiovascular disease.
The other problem is going to be overcrowding of the healthcare system. China built a hospital, Washington USA is buying an old hotel to convert to a hospital, Korea has only 5-6,000 cases confirmed and they are reporting being unable to handle the capacity already. In China many of the people who did not survive, would have had they been able to get access to the medical care they needed. The most recent data I could find indicated Spain has about 5,000 intensive care beds, which usually run about 80% capacity (1000 open).
There are almost 150 drug trials ongoing to evaluate the efficacy of anti-viral and other forms of treatment. There is hope that warm weather may slow the spread, but this is speculative at the moment. Until we have more information on this stuff, the only options we have are containment options like travel restrictions, quarantine, cancelling school, and restricting large gatherings of people.
The math is pretty ugly. I am of the opinion reality is better than the math, but worse than the general public is willing to acknowledge. I have been preparing to have honeymoon to BCN / IBZ cancelled by the airlines since Spain allowed Fallas to happen unmitigated.