Not true . High speed digitizers are available , at a price , but even if it were true that digitizing had to be done in real-time , how would this be "the rub" ? If you're too busy to listen to a tape as it's being digitized , then you're likely too busy to listen to the resulting digital copy , so why bother with digitization at all ?
I'd love to see one of these "high speed" digitizers. Can you show me one?
Well I could , only then I'd be doing your homework for you