The problem is that women already have a function that makes them nonfertile. Its MUCH easier to simulate that function, and at the end stop simulating it, than to create a completely novel mechanism to make a man nonfertile for a certain amount of time.
Granted, the pill isn’t exactly great, but there are quite a few options for women, and they all revolve around roughly the same mechanism. The alternative is shoving a mechanical device inside, and getting to the uterus (while exceptionally unfun) is still easier than getting to the testes.
The problem is that women already have a function that makes them nonfertile. Its MUCH easier to simulate that function, and at the end stop simulating it, than to create a completely novel mechanism to make a man nonfertile for a certain amount of time.
Granted, the pill isn’t exactly great, but there are quite a few options for women, and they all revolve around roughly the same mechanism. The alternative is shoving a mechanical device inside, and getting to the uterus (while exceptionally unfun) is still easier than getting to the testes.