we often use 'nand-gates' as a metric - in cmos they're about the smallest useful gate (other than an inverter) you can make - (4 transistors) - it doesn't mean

we often use 'nand-gates' as a metric - in cmos they're about the smallest useful gate (other than an inverter) you can make - (4 transistors) - it doesn't mean we build everything from nand-gates - in fact a std cell library usually has 30-100 gates in it and synthesis tools pick the right gates for the job as we compile up our chips