I always wondered about this as well. Linux regularly gains reverse engineered drivers and it seems like the same would apply. I guess this is probably how the hobbyist projects that drive the panels faster came about? I assume it's the same as the NDAs surrounding SoCs where the entire exercise seemingly only exists to spite the general public while serving no practical purpose. (Well I suppose pandering to nontechnical management's insecurities is a sort of practical purpose but anyway.)

But I was too lazy and/or uninterested to attempt low level tinkering with e-paper myself and these days you can finally purchase some reasonably(ish) fast panels off the shelf.