But I'm not a back-end engineer and I haven't dealt with web technologies at all. The only one of those things I've ever considered using is Hadoop and I didn't even know Yahoo had anything to do with it. Needless to say, none of those technologies are things I would be working on.
I typically write embedded and high performance C/C++ applications and I specialized in video at the time. I'm not going to jump ship for a position in some also-ran fiefdom in a directionless corporation writing embedded JVM UIs.
And that's the problem. Most people who are good in that niche aren't going to risk it with Yahoo vs some other firm or by starting their own company. Simply put: Yahoo can't win at that game because they can't attract the talent. So why do they even play at it?