Apple throws off lots of profits and thus is sitting on lots of cash. (Most of it overseas.)
As you probably know, Amazon profits have been marginal or non-existent. They use the net profit from some businesses to pay for expansion in others. To do that, they have to actually produce net profits in some of their businesses, i.e. keep costs under control. Bezos is using the older retail business to finance his newer, shinier adventures in digital devices. And the layoffs are exactly in the retail business, the cash cow business, to free up more money for shinier things.
AWS is not digital devices. Digital devices is Kindle, Kindle Fire, Echo/Alexa, etc.
Q4 results [1] say North America produced $1.7bln in operating income, and AWS produced 1.35bln. When Amazon says "North America", I think they mean "North American retail". So while international retail lost almost a billion dollars, I wouldn't say "AWS subsidizes everything".
(Edit: Q4 produces more retail profits than other quarters while AWS is probably steadier, so on an annual basis AWS probably produces a larger part of the operating income. But even so, retail has been operating income positive, so AWS isn't "subsidizing everything".
For the whole year AWS web services made more money than the entire retail operation. 4th quarter is usually good for retailers. That is why you have black friday the day the books become black, aka profitable.
As you probably know, Amazon profits have been marginal or non-existent. They use the net profit from some businesses to pay for expansion in others. To do that, they have to actually produce net profits in some of their businesses, i.e. keep costs under control. Bezos is using the older retail business to finance his newer, shinier adventures in digital devices. And the layoffs are exactly in the retail business, the cash cow business, to free up more money for shinier things.