I think you're overstating the early popularity of microcode a bit. Microcode didn't really catch on until the IBM System/360 (1964). The problem was that storage was very expensive so it wasn't cost effective. IBM had to invent weird new storage techniques (TROS, CCROS, BCROS) using transformers or capacitors to make microcode practical.
The same thing happened with microprocessors. Early microprocessors didn't have enough space for microcode so they all had hard-wired control logic. It wasn't until the 8086 generation that you could put enough transistors on a chip to make microcode practical in a microprocessor. The 8087 co-processor is an interesting example. In order to fit the microcode onto the 8087 chip, Intel had to use weird semi-analog multi-sized transistors. This let them store 2 bits per transistor in the microcode ROJM.
The same thing happened with microprocessors. Early microprocessors didn't have enough space for microcode so they all had hard-wired control logic. It wasn't until the 8086 generation that you could put enough transistors on a chip to make microcode practical in a microprocessor. The 8087 co-processor is an interesting example. In order to fit the microcode onto the 8087 chip, Intel had to use weird semi-analog multi-sized transistors. This let them store 2 bits per transistor in the microcode ROJM.