I don't buy this as an excuse. There are too many stories about Amazon culture to write them all off as a loud minority. Either Amazon has more bad departments than other companies or the bad ones are just worse. Either way I don't care, I don't want to work in a toxic environment and am not going to coin-flip that I get put into one of the good ones.
Though I blame it more on their slightly looser hiring practices. A lot of people get hired there that have no business working as engineers on hard problems anywhere. Then Amazon does what most tech companies seem to have trouble doing: can them (they should not have hired them in the first place, but still). Then they write stories about it complaining about how great they were and were canned.
You're suggesting Amazon struggles not because of bad management (as almost every story suggests) but because their developers aren't skilled enough? That's a really strange claim on the face of it.
That said, they totally have bad management. Like the majority of tech companies minus a couple of shiny ones. What I'm saying is that, aside from the fact they are a pretty visible target among tech companies with shitty management, one of their main issues is that they have very lax entry requirements, so not only people bitch about the real issues, they ALSO bitch about non-issues because a large segment of their devs suck. Yes.
Silly of you to claim amazon has lax hiring standards.