I would probably avoid looking into Clojure or Scala to make money based on popularity. Problem is that these languages are 'cool' which means that there is considerable amount of good programmers playing with them in free time and willing to take a job where they could code in that. Let's say that there are
- 2 million java programmers
- 2.1 million java jobs
Doesn't look good? But if you compare it to (completely random numbers)
- 50k Clojure programmers
- 1k Clojure jobs
Then the fact that there is 40 times less Clojure that java programmers is not going to help you much.
If you are trying to game the popularity, you need to find languages platform which are in some demand, skillset is rare and they are horrible to work with. With that, you may get into job which you will hate, but you will be paid a good money and have job security.
Look what is happening with game development. So many people want to work there that you work very long hours and pay is very low. I knew some people who were willing to get pay cut to switch from Java to Scala. They weren't learning Scala to earn more, but to have fun again.
From my experience, domain you work in has a lot bigger factor in salary than platform. Investment banking people will earn same money, regardless if they code C#, java, C++ or python, but might get considerably different packages based on domain knowledge and actual skill. Game developers will be paid badly regardless if they do Flash, Android (talking about salaries, not indie games) or C++.
Switching language in same industry can give you maybe 20-30% salary increase? Switching industries can double or triple it.
Examples:
C# developer with 5 years experience in banking
http://jobview.monster.co.uk/C...
600-700 GBP per day (which gives 130-150k yearly)
plus plenty of other 500-600 GBP per day jobs.
Web C# jobs outside banking (same city)
30-50k GBP yearly
and no offer for daily contracts.
Learning Scala just to move from 30k to 35k job is not worth it. If you want money, go for proper industry. Learn languages/platforms if you want to have fun in work - but then base it on what you want, not what is best paid.