It was never about the coach. It is, and always will be, about the talent pool.
Who are the great players Klinsmann and Arena left home? (Ignoring the Cameron/Johnson situations, which might be complicated by their clubs for all we know) Which players in the pool, be they German or MLS, weren't given a chance?
The talent problem predates Klinsmann and Arena by a decade or two. Either coach was doomed to fail, whether they played 100 lineups or they played binkies like Omar Gonzalez despite repeated failures in search of "consistency". They were both poor, but they were poor because the talent pool was shallow.
And the best players in the pool stopped developing, or regressed. Some was due to age but some was the result of poor career decisions by the players and their own lack of effort. The players who should have been the foundation of this cycle - Bradley, Altidore - too often were not as good as it appeared they might be. The best players on this team were the youngest - Yedlin, Pulisic - so maybe the talent is going to get better and this won't happen again.
Sir Alex Ferguson in his prime might have dragged this group of underachievers to qualification. Blaming the coach, either coach, ignores the real problem.