If M1 Macs could only run apps built for its ARM cores, then they’d have a limited market, so Apple has engineered a temporary solution branded as Rosetta 2. The eight cores inside an M1 can’t run code which has been compiled for Intel processors, because the instructions (and more) are different.
The most fundamental difference between an M1 Mac and all the previous Macs, since they switched to using Intel in 2006, is the processor.
