in this day and age how come we don't see laptops carry a physical on/off switch for the microphone and camera?
Gradually they were dropped from newer models because the manufacturers saw no sales changes due to the presence/absence of the switches (i.e., not enough purchasers refused to buy the "new" laptop because it dropped the physical on/off switch, which is the only feedback the makers truly understand and pay attention towards).
And dropping the physical switch saved the manufacturer a small amount on each laptop, which when multiplied across the numbers built was either a nice profit increase or a small price reduction (or likely a little of both).