Before they read is paper on the concept they built small scale models and hoisted them up in front of real radar and tested them... an extremely slow and expensive way of developing stealth aircraft because they didn't know what worked and what did not without testing it.
they had no way of predicting what would reduce a reflection and what would actually increase it...
Spike management just acknowledges that radar returns are 3D and each angle in 3D creates a different return from a specific direction and angle.
Suggesting these cockpit displays are some how magical is amusing... they wont operate in real time and wont distinguish the effect of different frequencies... for instance a metric wave radar is not effected by shape so the radar return from any angle will be strong... the display in the aircraft will know the direction the radar is coming from but wont actually be able to determine an angle that will reduce the signal from such a radar to evade it...