Reading the "How to Sell to Business" section convinced me as an engineer that I should not focus on Haskell. If Haskell programmers are a better deal for businesses because better programmers can be hired for less money, I should logically choose to be a Java programmer for the same reason.
The Java expert will be hired to maintain a million LOC legacy shitstorm, whereas in Haskell you'd have at least a few engineering guarantees you won't get a headache on your first day.
The paradox is that if you are focused on how to make the most money to the point that you are choosing your programming language based on estimated market value, you are likely not the caliber of developer that the top-tier tech companies are looking for. In other words, you can probably make $150k under an insufferable pointy-hair at any Fortune 500 company, but you won't get to work on cool stuff at Google or Facebook for $250k.
It doesn't necessarily work that way. Java programmers at the high end can push their compensation into the 250k+ range by starting bidding wars. It's hard to do that in a small community. In Java, there are so many jobs that it's really easy for a good engineer to set up a bidding war.
You have to be somewhat of a game-player to pull off the Java-engineer-bidding-war game. You have to be the sort of person who will work on the most horrible projects just to move up the salary scale. You also have to live in the Bay Area or New York, and use competing offers to drive up your pay every 2 years or so.
At some point, though, these $300-500k Java engineers at tech giants (who, by the way, are mostly paid in stock with vesting, so if you're bearish on the markets, their comp is more modest than it appears) are going to dry out and have to go into big-company executive roles. Playing that game rots your brain, because you're spending more time looking like a great engineer than learning new things.
Some people who are just as smart as me have better boredom-proofing and can work on enterprise Java. Good for them. I can't do it. I'd leave the industry before I'd maintain someone else's Java mudball.
