The difficulty is thermal. Microwave stuff operates in linear region, extremely fast and often extremely inefficient. Logic stuff almost always operates in sa

The difficulty is thermal. Microwave stuff operates in linear region, extremely fast and often extremely inefficient. Logic stuff almost always operates in saturation mode where its very slow but efficient. Old timers will remember emitter coupled logic ECL which went to great efforts to operate in linear mode at amazing power use, like 100 MHz IBM mainframes needed water cooling back when 2 MHz Z80s were considered fast. You could make something like ECL circuits using modern ICs but the thermal load would be like the surface of the sun and its cheaper to break the problem down into 10000 parallel processes that to make some kind of ECL.