Patents last for 20 years, that's a long time for something unique and groundbreaking to become mundane and seemingly obvious in hindsight, especially when almost everything these days builds on top of something already existing at a break neck pace.

But the problem with the current system is that everybody has to try to patent absolutely everything they come up with because if they don't somebody else might and then sue you for it, and instead of the patent offices actually doing their jobs and dismissing them outright so they would be free to use for everyone, they grant patents on the most simplest or broadest of things.

The silver lining is that plenty of great new things have been made specifically because people have been trying to avoid someone else's patents - "necessity is the mother of all inventions", literally.