Every aspect of this system has to be questioned relentlessly, because each of them requires huge investments of social and financial capital. I am happy to doubt the value of the private drug companies' contributions. Many of their discoveries are reformulations of older drugs meant to allow a repatenting and re-marketing of old ideas. Many of the new supposedly breakthrough drugs do not provide significant improvements in mortality, but do cost huge amounts of money so that they can recoup their investment.
There are of course important developments that come from everywhere, but the question is about signal to noise. If, as these statistics imply, you can show that the drugs and other changes in medical care that provide positive changes to quality of life and mortality are coming from government research significantly more so than other sources then why subsidize private research, why protect the private drug development system that results in outrageously priced drugs, why waste 2/3rds of research money to produce such a disproportionately small portion of the advancements in medical knowledge?
Again, I would like to see sources for the numbers, but regardless, there should be no assumptions made about the value of private or public investment because that's the way it has been.