To clarify, it's not the approval process that's challenging. It's making a safe and effective drug, then proving that it's safe and effective. If you achieve those, approval is pretty much trivial.
That's assuming that the Venn diagram of "proving that it's safe and effective" and "following the approval process" is one circle and there are no unnecessary requirements.
Which is demonstrably false, since e.g. the US and Europe have different requirements and neither is a subset of the other. If we accept that they both require adequate proof of "safe and effective" that means they also both impose unnecessary requirements, since otherwise the requirements would fully overlap.
That's assuming that the Venn diagram of "proving that it's safe and effective" and "following the approval process" is one circle and there are no unnecessary requirements.
Which is demonstrably false, since e.g. the US and Europe have different requirements and neither is a subset of the other. If we accept that they both require adequate proof of "safe and effective" that means they also both impose unnecessary requirements, since otherwise the requirements would fully overlap.