I wonder if that is true in reality. I know at one company I interviewed maybe 80 people. Of those I think 3 or 4 were hired. The point being it was hard to find qualified people. You could argue they should offer more money and they'd get more applicants. Say they offered 4x what they are offering now. They'd likely just end up with a bidding war with the other rich tech companies and so in the end nothing would happen (if all the companies raise their salaries then it seems arguable that there'd be little affect on applicants). Other solutions might be longer term like investing in education or hiring less experienced people and training. Others might be opening more remote offices hoping to find more talent in other locations.

All I'm really saying is as rich as Apple is I don't think hiring more engineers is as easy as just deciding to hire more.