Why Are Most Impact Craters Perfectly Circular? (Rather than Ovals)

A question sometimes asked is why an asteroid hitting a surface at an angle still produces a circular crater. Intuition suggests that there should be a smooth transition towards increasingly elliptical craters as the impact angle gets lower and lower. However simulations and experiments show that craters remain circular over most of the range of possible impacts.

Selected sources:
Clemens Rumpf - graph of impact angle vs instances ~0:54
https://agupubs.onlinelibrary.wiley.com/action/downloadSupplement?doi=10.1002%2F2017GL073191&file=grl55702-sup-0001-Supplementary.pdf
Hypervelocity impact experiment into sand at the NASA Ames Vertical Gun Range
https://www.youtube.com/watch?v=nbkkMKkjx6k
Visualization and Analysis of Threats from Asteroid Ocean Impacts
https://www.youtube.com/watch?v=95z0qRNFFxs
The transition from circular to elliptical impact craters
https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2013JE004477

Видео Why Are Most Impact Craters Perfectly Circular? (Rather than Ovals) канала Scott Manley