In most cases, college admission (for engineering or any other major) in the US is mostly or entirely based on some measure(s) that attempt of proxy academic merit (grades, rank, test scores).
Or are you referring to the most selective colleges in the US, which are relatively small compared to the national population (unlike in most other countries you name other than China) and where the usual measures have low enough ceilings and/or enough inconsistency that they are not adequate to get to the desired admit class size (unlike in the other countries you name)?
Of those most selective colleges in the US that practice holistic admission, Caltech is the one with the most emphasis in using holistic evaluation to find the highest level of academic strength in applicants, which is necessary because its minimum rigor level is very high compared to other colleges in the US.