Yes you’d certainly be right about that, and one can compensate for this by using a higher frame rate camera, or just making the digitization process a bit longer.
I don’t think we’ll see 75MP cameras within our reach anytime soon (it’s almost twice as many pixels as widescreen 8K). Besides, the analysis that I posted estimates that the Velvia 50 stock (which Rockwell claims is 75MP) is more like 16MP in practice, which is very much within our reach. Up to a certain point, all we’d be capturing is more distorted grain and not necessarily more image detail. The only reason I’d see scanning something in 75MP is if I were scanning 70mm prints.
I highly recommend you read this thread if you haven’t yet.
Some slightly off-topic stuff here:
If you’re talking about using OpenCV to automate film dirt removal, there’s a guy who used AviSynth to automate his dirt cleaning process as well as apply a bunch of other enhancement filters.
I also have written a fully-automated experimental film dirt removal algorithm based on neural networks.