Every human activity is improved with practice, there is no doubt more practice would have improved things but a lack of foresight and practice is not evidence of a criminal conspiracy. In 1944 the USAAF was sending out raids of 1000 bombers plus escorts from UK. They didnt have 1000 bombers in USA or any escorts in 1941. Germany declared war on the USA and the US responded there is only so long that any military force can say to their leader "we are not ready yet, just another few months practice"The part about faulty airspeed procedures causing the groups to be spread out starts in the 49th minute. He flat out says that no one thought of this problem previously. That tells me that in peace time they didn't do sufficiently realistic practice missions.