You can't coherently and simultaneously believe that markets are inefficiently pricing insulin too high and that the government should be imputing gigantic costs on firms that want to introduce new, unencumbered insulin products. The two thoughts aren't compatible.
Surely it depends on the barriers and how much of a cut those actually are in practice.
Furthermore, private corps aren't the only way drugs can be invented.
> Give companies, who are additionally acting unethically, a guaranteed and direct profit increase...
No, lowering barriers to competition doesn't give anyone guaranteed profit. It reliably does the opposite, depriving incumbent companies of their monopolies.
> Furthermore, private corps aren't the only way drugs can be invented.
Nobody -- literally nobody -- would dispute that. The question is whether the government is able to do the various parts of drug development as efficiently as the private sector. This is not a simple analysis, but I think the answer is more often than not, No.
Lets say the current price for insulin is $200. I see this margin, and say "I can produce insulin for cheaper, and I'm happy with selling it for $50". The government is placing restrictions on new competitors, so I can't just come in and sell insulin for $50. There is a restriction on competition, which causes artificial prices