Agreed - non North American airlines are getting better, and there really is no reason why they shouldn't, especially European, Japanese and other jurisdictions with strong regulation capabilities. The reason that North American airlines are not improving is that perhaps we are approaching the intended accident rates. Currently the North American airline fatal accident rate is 1 in 5 million departures or better ~ 1 in 7.5 million hours. Typical requirements are 1 in 10 million to 1000 million hours for hazardous events (small number of deaths) and less than 1 in 1000 million hours for catastrophic events (multiple deaths). From a pure technical perspective (losses due to systems and component failures), they account for ~1/30 of the events, meaning the technical failure rate is ~ 1 in 220 million hours, which is very close to the 1 in 1000 million hours goal. The biggest source of accidents now are related to operations and essentially human mistakes.

This is the reason for safety obsession - we are now in the situation where the events are so rare that you have to be absolutely obsessive to make the rates go down further - the easy wins are over, it's now about absolute fastidiousness...