How about you guys start a film resolution thread in the technical section.
Ask an archivist, and you will get the answer that film can definitely out-resolve 4K, because we see it do so. We handle hundreds, if not thousands of films in our careers and spend our lives looking at them at the grain level.

Ask a cameraman, director or DoP or researcher and you will get different answers from each and every one, depending on the few stocks they used, the few tests they may have done and their mindset and motivation/bias (which we all have). They tend to look at film in motion, on a projection screen or moviola, but rarely up close, and even a prolific director, not all that much film, it will be in the tens, bit the hundreds or more. Often the tests don’t say which MFTs used etc. The stocks used, the lighting setups etc etc.

Anyway, I can’t tell you the absolute maximum resolution film can reach, it is as much lens, light and processing dependent as it is on the stock, but in our experience we see it outresolving 4K, not in theory, but in our actual work. I can’t however say exactly how high it might go.

So let’s start a new thread if we want to get into the nitty-gritty, I’m happy to contribute and learn from it, but I’ll try and stay on topic here.