Just like the typical plumber or electrician, most programming is not "new products". Even today, most programming is probably Java (formerly Cobol) internal to a business or other large organization.

There will always be a need for programmers, for much the same reason we will always need plumbers: even with standardized parts and methods, you still need someone to actually customize it to the specific task and implement it locally.

This is where Free Software comes in: we need a commons from which those implementations can be built from. Unfortunately, we still have a lot of sociopathic businesses in the market that think it would be really profitable if they make the threads on all their pipe fittings in the reverse direction at non-standard sizes with the hope of cornering the entire pipe market. In practice, of course, all they've accomplished is forcing every plumber to keep a huge set of adapters in their toolkit and waste a lot of time matching them on every job.