Only explanation is that at least on state-level, MahagaTHbandhan is being more effective in mobilizing their core demographics
So I do not think there is something wrong with strategy part.
I don't think Raghuvar or Mamaji, or Vasundhara or Devendra or Khattar or Rupani/Anandiben or Yeddy screwed up exceptionally during their tenures as CM in these heartland states of BJP.
Opposition has oiled the procedures to help each other effectively to save their existence.
The resistance will vanish exponentially if BJP crosses this barrier.
Near the speed of light, mass of particle increases exponentially.
But at light's speed, one is massless. 😀