I'm just an armchair speculator so my opinion might even be slightly negative value but it appears to me that there just isn't any coordinated leadership at the national level that has tried to implement or expressed interest in implementing that.
One of the difficulties is that the countries that have good, science-led national leadership have concentrated on stopping the spread (just thinking about Finland with its national health system for instance). Countries with chaotic and uncoordinated responses, like the US, are too chaotic and uncoordinated to collect good data for research as well. There are not coordinated, science-led countries that let a lot of people get it for research purposes. Countries like Italy and the UK that got overwhelmed just didn't do this type of systematic research because they were busy. In the US some large insurance systems are doing research, but they're not necessarily incentivized to share their knowledge or data.
