I understood what you were saying, I just didn't understand what its relevance was to modern aircraft operation.
Modern planes operate in an electronic age - they are subject to air traffic control regulation which relies on electronics because of the complexity of present day routing. A mechanical instrument might simply add another potential for faults - what happens when a mechanical altimeter develops a fault and gives a reading that differs from the digital one - which one should the flight deck crew believe?
In the main, instrument failure is not a major cause of air accidents - statistically human error accounts for around fifty percent of all air accidents, with mechanical failure (engines/wings etc.) coming next, followed by weather.
Modern aviation technology is so good that a passenger jet can take off in London, fly to Beijing, and land, all without any intervention on the part of a pilot.