The 1st factor one may be biased by Amazon's larger employee base, which according to Google is currently >500k.
The 3rd factor is a big one and may be heavily biased by Amazon's exploding stock growth and horrible vesting schedule.
The article calls out Amazon's frugality as appealing to workers. If this is true, then human beings too easily act against their own interests. As a consumer, I appreciate their frugality toward their workers. As a worker, I would tell them to GFYS (in fact, I did). Their frugality does not translate to higher comp.