In economies that revolve around credit/debt (the US), once credit stops EXPANDING, that's a huge force pushing the economy down.
If everyone's already taken on as much debt as they can, and interest rates aren't consistently marching lower for ~25 straight years, it's going to be a little harder to grow.
Doesn't make it impossible, just harder.
We're paying for growth we got 25 years ago now.
Wish we invested that money better. You can't change the past. But you can change the future.