Macros were invented such that macro expansion does NOT happen at runtime. Lisp designers were implementing languages in the 70s which were used to develop who

Macros were invented such that macro expansion does NOT happen at runtime. Lisp designers were implementing languages in the 70s which were used to develop whole operating systems for computers with less than one million instructions per second. With window systems, networking, etc. A big part of the history of Lisp is how to design the language such that it is efficient AND/OR dynamic. Lots of people invented clever memory management, clever implementation techniques and adjusted the language for efficiency. The first self-hosted Lisp compiler appeared already in 1962.