Keep master copies of drawing sets on a couple of large disks while they are active. Run off a set of plans on microfilm or fiche. That doesn't mean technical drawing hardcopies go away. Most of us still see things better when looking at a great big plotted out drawing, than we do looking at what we can see on a screen - even a fairly big one. Drawings are still effective ways to pass data around for comments.
Drawings are still useful in the field.
Needless to say, plotter makers have figured all this out. They have different solutions with different features, at different prices. Without any doubt, the high ground is held by the LED plotters. At present, these plotters are strictly monochrome devices. They are costly.