Mylan had a government-enforced monopoly on the market, due to an over-zealous FDA effectively banning any competition that tried to enter the market. The USA has one supplier of injectible epinephrine. Europe has eight.
Mylan also smartly played the “isn’t anyone going to think of the children?!!” game, and convinced governments and school districts everywhere that THEIR epi-pens should be the ones used by school nurses and doctors around the the nation.
There was NO free-market for this product whatsoever, with predictable results.
You forgot to mention that Sen. Joe Manchin (Dem., VA) is the father of Mylan’s rip-off chief, Heather Bresch.