While it's true that intellectual products like new algorithms don't take huge numbers of people to produce -- so you'll be facing some competition to get these jobs -- I wouldn't totally write off these technologies as useless.
- Android and iOS devices both include speech recognition engines. Witness the much-hyped Siri. As far as I know, Hidden Markov Models are at the heart of most speech recognition algorithms; it's possible that Bayes nets are in use here too. And the speech recognition engines, though impressive, still leave much room for improvement. That means room for competition.
- The government funds a great many contractors that you've never heard of, who are trying to develop both old-fashioned database systems, and fancier statistical analysis tools including semantic networking tools, for understanding intelligence data. I imagine Bayes nets either get used here, or could be used.
- Robotics is very slowly taking off, not just in defense and in a few "silly" consumer applications like the Roomba (though it has some sophisticated competitors that even do SLAM!), but also in warehousing and factory automation, and we're just beginning to see the very leading edge of agricultural robotics. The world won't need a billion roboticists, but it is one more area where these sophistical tools can actually be useful.
I also think that games have a lot to teach these other fields. Sure, they don't need to deal with uncertainty to the same extent, but one thing they do a great job of is producing usable interfaces for interacting with the real world (or simulations thereof). People are beginning to acknowledge, for instance, that Starcraft is a pretty good model for what a good "net-centric warfare" interface should look like. Indeed, it was by explicitly following a strategy of copying Starcraft's UI that Ed Olson and his students won the recent MAGIC robotics competition in Australia. The difference, of course, is that instead of loading a map file you're doing SLAM, and the "fog of war" is real! My point in bringing this up is to say that, although some of these algorithms don't get used in games themselves, they get used in other fields that involve many of the same things as game development.
You are definitely right about game having a lot to teach other fields.
Robotics usually focus on reinforcement learning type stuff.
Yeah contractors, data scientist are the prime users of bayes nets. They have the resources, expertise and time to build, train and sample from networks (sometimes measured in days). The lack of black box also means that the parameters themselves may have actionable info.
HMM mostly, never heard of bayes nets though Condition random fields gaining in use.
Siri is stupid (not an insult) - I read from someone who worked on it that its mostly keyword matching.