Care to back up your claims?
I supposed that the reasons are so evident, that no further explanation was needed...
BTW The basic reason is the number of components and soldering points
Look at the single key: keycap, stem, upper and lower switch housing, two metal contacts, a spring, on blue switches there's an additional piece, then the diode or the led required on some keyboards.
This mean from 7 to 9 pieces per key, so from more than 700 to more than 900 single components per keyboard and from 300 to 600 soldering points.
Now compare this with a basic rubber dome keyboard : 103 keycaps, a dome menbrane, the three layer contact membrane, zero soldering under the keycaps, maybe less than 100 on the whole keyboard.
What do you think is statistically more prone to fail ?
Then the higher protection against liquids and dust.
Then the lower weight which protect the RD keyboard from accidental falls
Then the number of the keyboard produced that helping to iron out the early production defects and the evenness of the whole production.
I can continue, but I think you should have the idea.
P.S. just to be clear I mentioned microswitches keyboards for a reason, Model F (switchless), Model M (membrane) and Topre (switcheless rubber domes) are obviously not included, they are usually both reliable and durable.