I don't rlly understand it o.O? These stunts are easy, so how could they be hard in the past? heh?
Hmm.. dunno xD
Many different reasons,
1. We didn't have that many techniques, for example RAD wasn't very well known.
2. Most people were still getting used to how to bump.
3. Not that many stunts were known so it was harder to get better when you only tried the same ones over and over
4. Hardware has come a long way since then so people get a much higher FPS now which makes stunting easier.
etc. etc.
This is from when stunting was fun, none of this "you lamed that stunt lol" or "old stunt lol" shit. Love it.