I'll relay another joke from set:
A new Assistant Director comes on to help the second unit on Gone with the Wind. He finds the script supervisor.
AD: How much are we shooting today?
SS: One eighth of a page.
AD: You're kidding! We'll be home in an hour.
SS: I don't think so.
AD: What do you mean? What are we shooting?
SS: Atlanta burns.
The point is that it's an inherently fuzzy process, and heuristics work a lot of the time, but nobody cares about a system that works a lot of the time.
If you design something better, I'll be glad to use it (hell, I'll help you design it), but please don't be so quick to judge. It's a business of edge cases, and it's been built as such.
If it makes you feel any better, a lot of multicam shows and studio shows have switched over to all digital script distribution that's automatically distributed. But there is absolutely no replacement for a paper script for a lot of really compelling reasons.