For problems that can be solved with only a small amount of simple code that is true. However software can become very complex and the larger/more complex the problem is the more important software developers are. It quickly becomes easier to teach software developers enough of your domain than to teach domain experts software.

In a complex project the hard parts about software are harder than the hard parts about the domain.

I've seen the type of code electrical engineers write (at least as hard a domain as software). They can write code, but it isn't good.

That's true both ways though: if a theoretical physicist wants to display a model for a new theorem, it'd be probably easier for them to learn some python or js than for a software engineer to understand the theorems.