It's not black and white- in pharma there are notable sources for investment that are not private, e.g. for orphan diseases that would otherwise not see enough investment due to lack of profitability.

But here's a mechanism to mobilize private capital for those diseases that are. Again, the investment needed boogles the mind, around 10B currently, for a single drug.

You're asking someone to pay that money and allowing others to reap the rewards. Why wouldn't everyone want to be the one who didn't pay the money?