Let's see here:
2000-2006
800m: 1:43.8
1500m: 3:31.9
mile: 3:48.9
3000m: 7:34.9
3000st: 8:08.8
two miles: 8:11.4
5000m: 13:10.1
10,000m: 27:13.9
marathon: 2:09:41
Seems like we have improved or at least stayed around the same level as in the 70's/80's. Problem is there are now dozens of East Africans who make these times look like high school marks. If Africans realized thier talent and had the same agent/money oppurtunities of today, everyone in the 70's & 80's would be calling Shorter/Salazar/Pre/etc punks for finishing 15 seconds behind the winner and outside of the top 10 at the latest European race. There also wouldn't be handfuls of marathoners willing to sacrifice time and energy to finish 3-5 minutes behind a faceless and generic winner.
Personally, I'm happy the way it is. I'd rather have someone struggling African win thousands of dollars and get glory than some over privileged suburban white kid. The talented runners in this country still have the motivation to pursue their dreams; who cares if we don't have 100 people running inbetween 13:15-13:25/27:40-28:00/2:15-2:20, it's just running!