Why do some people say that C ++, Java, and PHP are hard currencies for programmers to find work?

A statement we saw tonight said, "C ++, Java, and PHP are the hard currency for programmers to find a job. If they are familiar with one of them, they are not afraid to starve to death ." Are these three very demanding markets? Or are there other hard currencies for programmers? The "hard currency" here refers to the ability to find a job even if these three courses are well learned. That is to say, the market demand is very high. However, I have heard this statement, so I'm not sure whether this statement is in line with objective reality. Therefore, I want to prove whether the market demand is really strong. A statement we saw tonight said, "C ++, Java, and PHP are the hard currency for programmers to find a job. If they are familiar with one of them, they are not afraid to starve to death ."
Are these three very demanding markets? Or are there other hard currencies for programmers?

The "hard currency" here refers to the ability to find a job even if these three courses are well learned.
That is to say, the market demand is very high. However, I have heard this statement, so I'm not sure whether this statement is in line with objective reality. Therefore, I want to prove whether the market demand is really strong. Reply: The language is very simple. Even C ++, which is known for its complexity, lacks value in simplicity. For programmers, familiarity with languages (not dare to write "proficient") is only a basic requirement. To be a high-value programmer, you still need to know a lot of other knowledge. Including and not limited to Compiler Principles, operating system principles, and database principles. Will ruby be starved to death? Will JavaScript be starved to death? Not necessarily. Do not trust hard currency or anything. Programmers rely on imagination and solid foundation instead of tools to make money. Familiarity with one of these three types does not starve to death, but this logic applies to any other widely used language. JavaScript code ...... I agree that language is always a tool, and each language has its own limitations and applicable scenarios, only when you have the ability to solve systemic problems can a single feature of the language be more effective. At this time, you will be more valuable. net or something ~~ Most of the requirements are true, but they should not be for the language itself.
For more information about high-end jobs and long-term considerations, see the in ten years article mentioned in the answers and comments of vczh.
Below the high-end, you may not see it. c ++ usually requires familiarity with engine technology or linux systems, java with various frameworks, and php with various peripheral technologies developed by web applications.
The word "familiar" is not so easy to use. It's just a common tool in some fields-so you can say something about code. However, the popularity of tools will always change. At that time, it will not be a language for programmers to preserve the value. The same principle is true for "Learning Mathematical Physics and Chemistry, not afraid to go all over the world ".