Compiler-generated code never uses the complicated instructions provided by many computers. Overall, it is better to build a very fast processor with comparatively simple instructions and implement complex calculations in software.
Memories can be large and relatively inexpensive.
The shift to RISC processors in recent years has been motivated in part by technological changes. This was important at a time when RAM was small and relatively expensive. It is characteristic of RISC architectures that Instructions are of a few simple and regular forms. Processors provide many registers. Control is hardwired, being comparatively simple.