Except that isn't how it works, and could lead people to buy a library for a day, then opensource it.

Open source means any code used is widely available to anyone. Having a library you pay for means it cannot be widely available, or nobody would buy it. No more licensing game engines, paid libraries cease to exist since there is no incentive to make them, everything goes the "open source way" which means hard to use, opinionated, unintuitive software that is maintained by random people who rarely know what they are doing. No online banking, since you can't certify that easily and it wouldn't be profitable. No card with points and goodies in your supermarket for the exact same reason (points have a calculable value in real money). No online healthcare, etc etc