alt Hacker NewsThe defense against Bayraktar at the beginning (the big column to the north of Kiev) was dismal because AA assets were turned off, not because they were unable to shoot Bayraktars.
The problem was command and coordination.
Darwin worked and Russians learned (as did Ukrainians).
Regarding your last point: In peace time, you want to prioritize hiding your true capabilities (perhaps inflating them in (misleading direction) to deter them from attacking). Once the ware breaks out, you want to improve your capabilities as fast as possible.
With Bayraktar it was a software update for radar that allowed for Russian to destroy them. The radar signature of Bayraktar was way off from a typical target that radars were looking for at the beginning of the war.