As someone more used to baseball than cricket, why don't more bowlers favour the nearly sidearm delivery that he uses?
Because it's incredibly unorthodox, and hard to replicate. If any other bowler, even one of the best in the world, ran up and tried to do that he'd bowl wide after wide, but given enough practice you could probably work on it. Bowling actions are incredibly rhythmical and repetitive though, bowlers work for years to get their run-up and bowling action to become muscle memory, so you'd probably have to work at it from a young age or completely change how you bowled during your career. It's also a little bit controversial as some thing it should be illegal. I wouldn't be surprised to see more young bowlers of the next generation trying it, though.
Incredible run-out whilst I'm typing that.
