Classic RISC CPUs like ARM and MIPS basically offer the trade-off: simple instruction set, but instructions execute in one cycle for good overall performance. (It gets more complicated in later times, but I'm talking about seventies and eighties technology.)
But e.g. the 6502 is in many ways quite simple, yet takes a minimum of two cycles per instruction. I'm guessing that could have been one cycle for the simplest instructions, but only by making the chip bigger, and low cost was the primary objective.
Which leads me to conjecture that a simple instruction set doesn't automatically get you one instruction per cycle; maybe the classic RISC CPUs took the transistors saved on complex instructions, and spent them instead on things like full-width ALUs and extra pipeline stages, or whatever ways there are to make a CPU run faster, and that's why they execute many instructions in one cycle.
Which would seem to leave a niche for a RISC CPU that has a simple instruction set, fixed format and load/store, that executes most instructions in two cycles and is extremely cheap. If such existed, that would seem to be evidence for my conjecture; if not, then maybe I am misunderstanding the trade-offs.
So did any such CPU ever exist?