Why is the 100m men's world record being broken so often?

Question

In the 80s and 90s, some of the records stood for 10 years at a time. Even in the 90s, the height of the steroid era, the WRs stood at least for a couple years. Now it seems like every other event has a new world record.

Before anyone says steroids, I accept they are all nearly using roids, but they were in the 80s and 90s as well and the records had more sustainability. What is going on in the last couple years that has the records falling so often?

Answer 1

the american science doing miracles nowadays with steroids!

Answer 2

Better technology all around. Better understanding of what the body needs to function at an optimal level (thanks to technology). Better shoes, better training exercises.