The investment you make in your skills also follows a similar pattern to financial investments, i.e. high risk equals high reward.
In 1995, if you had told me to invest my skills in this little known language called Java by a small company called Sun Microsystems, I'd have rebutted you saying you've probably had a few drinks too many! Who would have thought Java will be used to write just about anything (including mobile apps) some day?
On the other hand, had the "risk taker" in me had jumped on the Blackberry development in 2010 or Windows Phone development in 2015, his career would have failed quite miserably!
Similarly, had the "risk averse" buddy chosen something like COBOL or C in 1995, he'd probably still have a low paying job to stick with for several years to come.
You might have spent a few years on low pay sticking to COBOL, but COBOL programmers have become rare in the last decade or so, and can demand high fees for maintaining old bank systems. Similarly, C remains popular and the language has been updated.
It may be necessary to diversify; when BlackBerry first came out, they were very popular and profitable. It wasn't possible to predict that they would vanish so quickly. In the 1980s, the investment adverts said, “Where were you when Polly Peck was 17p?” or similar. That was one of the companies whose share prices multiplied by about 100×. Who would have predicted that its founder would be convicted of fraud and the company collapse ten years later? But diversifying one's investing would have allowed one to make a profit despite that.
This is what the risk-takers tell you. But of course "equals" isn't true. I know at least one person who won the lottery and lost all the winnings in the stock market. It may be that high reward requires high risk to get it, but there's no guarantee. You hear about the people who took high risk to get high reward, but that's just publication bias because you don't hear about all the people who took high risk and got no reward, or even negative reward.
As for your question, I don't have any advice about what hot stocks to buy... sorry, what languages and frameworks to learn.