More and more I think it is. Game books without much authorial voice (i.e. most every game book published these days, i.e. game materials by committee and such) are not fun to read. Sometimes the stars are right and I can get into well written setting and stuff - but most of the the time, meh. I do in various ways enjoy reading T&T, Paranoia, Gygax - but for book use, it's the lists and the tables I'm after. I've had one experience with a DM aid - a ref screen for AD&D. Loved it. Handy.
I'm really glad to see that the 'DIY ethic' has caught hold with so many other people of and near my generation - not something I see much of in my day-to-day local life.
Isn't it really just about the ref sheets? Pre-prep organization work, tweaking frequencies on random tables... not just that - it's really about sitting down and playing. Or pacing, as you see fit...
Ramble much? yug.