Why does a rotating tire use the static, rather than the dynamic coefficient of friction?

I am not sure why you are rejecting the static friction on the basis on long the parts are in contact. A "bond" is not a chemical bond that might take time, but rather an interaction between adjacent molecules, or atoms. It propagates at the speed of light, so there is plenty of time for the adjacent molecules to "bond" when sufficiently close enough.

In real life though, pairing down the tire/road contact into a friction coefficient is the wrong approach. It is a non-linear contact, where the higher the normal load the wider the contact patch is and the distribution of contact pressures changes. In addition, some parts have micro sliding as only 1 point in the contact patch is truly stationary.

There is something called the "Pacejka Magic Formula" which is a well established model of a tire contact, and there are newer ones out there which minor and major refinements to it. In the end, it depends on what you want out of it, in order for you to decide what contact/traction model to use.

[ref: Magic Formula]

A car drives at 20 m/s. The circumference of the wheel is 2m, so the rotation rate is 10 Hz. A reasonable percentage of the tire is in contact with the ground - maybe around $5\%$. That would give a contact time of $5\times 10^{-3}$ s.

This is a pretty long time in molecular terms. The distance between molecules divided by the speed of light is around $10^{-18}$ s, so that's the fastest we can imagine some sort of bonding occurring. That 16 orders of magnitude faster than the contact time.

Real chemical reactions must be slower, but with $10^{16}$ "clicks" of time for the chemistry to sort itself out, there should be plenty of time for the tire to stick.