Again, I am not a pilot, I am an EE by training.
@Mahatma Kote
though why aren't technologies like doppler airspeed used instead of pitot?
Normal radar doppler only reflects off airborne particles like dust, water and ice. It passes right through air, so it cannot directly measure airspeed. If it gets reflected by air, then it would not be able to measure anything at all, as it will get absorbed the instant it leaves the instrument before reaching the air you want to measure. The same reason why those probes protrude out of the fuselage of the aircraft.
I did a google search and found
Calibrating airborne measurements of airspeed, pressure and temperature using a Doppler laser air-motion sensor | OpenSky - Providing free and open access to the scholarship of UCAR, NCAR, and the UCP which uses laser to measure airspeed, but considering that the paper was only written this year, it is not likely to reach the aircraft for at least a couple of decades, even if it gets there.