A very important point which I have not seen anyone make is that RISC is not only about having simple instructions and implementation BUT ALSO doing that in a w

A very important point which I have not seen anyone make is that RISC is not only about having simple instructions and implementation BUT ALSO doing that in a way that does not harm performance. The early simple computers also had very poor performance, not just in an absolute sense (of course they had primitive circuitry) but RELATIVE to the technology they used e.g. the delay needed to clock two values into two sets of latches (flip-flops), feed the output into a full-adder, then clock the result into another (or the same) set of flip-flops. How fast can that clock cycle be in the technology? Now take some fixed task and measure how many of those clock cycles it takes to complete it. The much-maligned Dhrystone will do. How many instructions are needed to complete the task? How many full-adder clock cycles in total do those instructions take? Modern RISC does a good job of minimising those clock cycles while using a small amount of hardware. The first computers used a lot more clock cycles. That applies to not only the first mainframes but also the first minicomputers and the first microprocessors. They were simple in a way that seriously hurt performance.