Compiler optimizations make up for it, usually. Thats been my experience at least.

An important thing to keep in mind is just how far compilers have come over the least 40 years. Often, with immutable languages, they can do extremely efficient compile only optimizations because of said guaranteed immutability by default.

Its not true in every case, of course, but I think for most situations compilers do a more than good enough job with this.