I don't quite get it. In years gone by it was highly unusual for runners to hit the deck in a race. It was so rare I even remember the more famous incidents: Ron Clarke in a mile race won by Landy in '56; the famous fall Viren took in the 10k at Munich in '72 and then got up to win; and then the "biggest" of them all - Mary Decker being tripped by Zola Budd at LA in '84; and lastly, El G falling at the bell in the 1500 in Atlanta '96.
But now it seems that it is almost inevitable that there will be falls in races that are run out of lanes - it can be virtually guaranteed at changeovers in long relays. Runners appear increasingly poor at judging their distance from other runners and at changing their position. In many races now I would expect a fall will likely play a part in the outcome of a major race. If it is a more frequent racing hazard now I can't see the reason for it.