The drug industry would have you believe that there will be less research and development under a single payer system.
In fact, much medical research is currently funded by the National Institutes of Health.
Under single payer, this would grow.
Also, drugs will be cheaper under single payer.
When all patients are under one system, the payer wields a lot of clout.
For example, the Veterans Administration gets a 40% discount on drugs because of its buying power.
This single payer buying power is the main reason why other countries' drug prices are lower than ours.
Now you know why the drug industry is so opposed to single payer.