Why are most jobs just about web development or mobile development? (I'm not criticizing I'm a mobile developer myself)

Is it JUST purely because of the market need and people using them?

Share your opinion on this one and what other career paths in CS do you know about you think would benefit from more people in them.

The demand is very high with web and mobile markets. It's my observation with job market and with offers here in the north.

I've got two freelance offers, yet I haven't been able to start the business yet. I've got a stable job with very flexible contract and studies still in progress. Just turned 18.
It's extreme.

It's the time too. At the time businesses are handling money like a hot potato. The time to invest.

If you are into research type of jobs:
Then try Data Science and Machine learning.