I find it quite shocking that C++ jobs don't seem to pay as much as JS/Python/Mobile dev

I've been an iOS dev for 5 years but I was feeling like I'm getting too tied down in one language/ecosystem so I thought about expanding. Then a C++ job offer came tumbling my way and now I'm thinking of whether to take it or not.

While this job comes with a ~30% pay bump, I went looking around and noticed that C++ jobs typically pay ~70% of what Android/iOS/Node/Django/React job listing say (in the same regions). Go look it up on AngelList, SO Jobs, LinkedIn, pretty much everywhere.

I only know kiddie C++ from college, I always imagined "real" C++ (C++ 11/14), given that it's so much more difficult (not difficult per se, just in comparison with) python/Java/Javascript, that it should pay significantly more.

Who would want to work harder on something far more complex for lesser money?

What I'm getting at is, is C++ a viable career option in 2018?

Yes, I know

C++ isn't going anywhere

and

"real" systems where "performance matters" like operating systems, firmware, embedded systems, server tech, core machine learning tools, audio/video/graphics/games related stacks etc will continue to use C++ for the foreseeable future

I get all of this, but I'm starting to wonder the actual viability of finding a decent paying job in C++ when the world is practically overflowing with job openings for web/mobile-devs/data scientists etc. I know C++ isn't going anywhere, but why does it not seem to have high(er) paying jobs compared to these?