Some technologies, even if they are popular today, die a death of slow attrition. There may be demand, but it's niche (like COBOL today).
C (and C++) will remain popular for a longer time for a number of reasons; after all, under the hood NodeJS is a C program right? Because it's the most useful portable macro assembler anybody has invented, and it forms the basis of nearly every higher-level system.
In the context of this discussion Perl is an exception that proves the rule.
There are no Perl jobs because Perl was supplanted by Python and Ruby and embarked on a disastrous Perl 6 journey.
This will not happen to node.
JavaScript is and will continue to be for the next 10 years the most popular programming language ("popular" == "most jobs") because it has monopoly in the browser.
As a result JavaScript will continue to be used in other domains (backend, desktop, mobile) due to sheer number of JavaScript programmers. Quantity is a quality of its own.
So node (and deno and bun) will continue to be used and there will be plenty of jobs for JavaScript programmers ("node" programmer is 90% JavaScript programmer and 10% "node specific APIs" programmer).
Of all programming languages that you worry might disappear in the future, JavaScript is at the end of the list.
