> "not because it's unspecialized, but because it's hard to fashion a value proposition for it relative to your competition in the market."

I agree with this entirely. But it makes me realize that perhaps I haven't explained my position well.

I would agree that being a mobile expert is likely going to be LESS lucrative than being, say, an expert in recombinant DNA technology with a fluent C++ background and a PHD in machine learning.

The only issue I see with advising people to invest tons of time and money into niche fields, is exactly what others have pointed out in this thread - You can't really predict what's going to be valuable in 10 years.

So take your pick - Go the safe route and become an expert in a more general field like, for example, mobile. Or pick something incredibly niche, which will shrink your competitor pool and increase your relative value proposition. A classic risk/reward scenario if I've ever seen one.

> Go the safe route and become an expert in a more general field like, for example, mobile.

I don't think this is all that safe, really. What we consider "mobile" development has really only been around for about a decade with the releases of iOS and Android. (Sure, there were mobile platforms before that, but most people didn't really care about them, and specializing in them would likely limit your options, not expand them.) In that time, mobile development has gotten nothing if not easier. So, over time, being a "mobile dev" will become less and less of an important specialization. More people will do it, and the frameworks around it (both those released by Apple/Google, and third-party things on top of it), will make it easier and easier. By that point you might be an "elite" mobile developer who can do certain things on mobile that most others cannot, but the market for that level of specialization will likely also be small.

What about specializing in a platform or language makes it hard to fashion a value proposition for it relative to one’s competitors in the market? (Not disagreeing; just trying to wrap my head around this. Also, I think your comments in this thread have been super useful.)

Every senior developer in the market who codes at all in your platform is going to represent themselves as a subject matter expert in that platform.

To make matters worse, developers will disagree with each other about what the Right Answers are for a given platform or language or engineering approach.

Cryptographers (as a counterexample) also disagree with each other about the Right Answers in crypto. But serious crypto people are generally competing for jobs only against other serious crypto people, and there aren't that many of them.

Moreover, the general domain of cryptography isn't going anywhere. But look at Objective C, or Windows Mobile.

Finally, proving value as a subject matter expert on a language or platform depends on companies having hiring processes that reliably spot expertise. But, of course, hiring processes do a terrible job at that.

Thanks so much for the response. Can you say any more about what kind of domains tend to be lucrative? It seems like all your examples (distributed systems, sensor fusion, software security, OS kernels) seem very “technical”, for lack of a better word, compared to, say, knowing a lot about the health club industry (a different example mentioned in this thread). Do you think that’s an important distinction?

I think knowing a lot about a particular vertical is hugely distinctive and valuable, often more so than technical specialties.

Thanks :-)