It's not sustainable for amazon-ish [1]. They offer higher wages than competitors because they need to keep accumulating new employees or convincing old ones to come back.
Do they? Ten years ago Walmart distribution center workers were making what the writer says he made at Amazon, which is itself surely the result of recent increases. No idea what Walmart pays today, especially in these post COVID-induced work and price changes. Four or five years ago, on the other hand, I'd heard Amazon was around $13 to $14.
Sure it is, as soon as you realize employees are replaceable commodities that get used up like break pads.
Sustainable for the individual? Obviously not. Sustainable for amazon. Of course, which is why it won't be changing.