My guess is that there were two aspects to the economics. First, Motorola's price included a big profit margin, since the price rapidly dropped when the 6502 pr

My guess is that there were two aspects to the economics. First, Motorola's price included a big profit margin, since the price rapidly dropped when the 6502 provided competition. Second, if HP already had paid for a metal-gate fab, it was probably cheaper to use it than build a new fab.