What you’re suggesting is any crash can be attributed to the US method of scheduling takeoff and landing (since that’s the risk issue you’re responding to). That’s not true. If a plane’s engine explodes in midair, it has nothing to do with how the ATC schedules takeoff and landing.

I couldn’t find any crashes listed on Wikipedia in the past 20 years that could be attributed to two planes being directed occupy a runway at the same time.