I've met few (very few) guitar and bass builders to whom I would apply the "L" word.
Usage or non-usage of power tools has exactly nothing to do with it. Stradivarii and Guarneri would have used them if they had them, I would bet. Anyone (well, almost anyone) who's trying to realistically make a living building instruments will use them.
(That reminds me of a cabinetmaker friend of mine who playfully scoffed at the idea of sandpaper, saying that "real" furniture builders only needed a cabinet scraper....
In my book, that "real" furniture maker will be the most impressive guy on the welfare line.)
This has everything to do with the accumulation, synthesis, and application of knowledge. People like Ken Parker, Mike Tobias, and Uli Teuffel are unbelievably interesting to talk to about guitars, but here's the more relevant part - they know and understand a whole hell of a lot about other subjects and disciplines that are related.
Mike Tobias was/is a classical guitar builder. Solidbody basses are a successful application of those skills.
He knows about where the woods come from, how they grow, and all sorts of other ephemera. He has a strong grasp of the history, the engineering, and the musical side of guitarbuilding. He is much more than a solidbody bass assembler, which is precisely why his solidbody basses are so damn good.
Ken Parker is a machinist and industrial engineer.
The Fly guitars were one result. His 3lb, $30k archtops are another. Ken can talk intelligently about almost anything. He knows materials like few people I've ever met. This breadth of knowledge comes together as instruments that very few other people could make.
Uli Teuffel is a serious industrial designer. He designed and patented a plating process that is used on every new Audi that's made. He's also a very serious and knowledgeable modern art connoisseur...look at his guitars, and that becomes clear enough.
The point is - all these people are incredibly badass craftsmen. However, they make my "luthier" list because their formidable woodworking skills are secondary to, and in service of, a level of understanding and perspective that allows them to make conscious and informed decisions.
I've been building for 8 years now, and have built (completely or mostly) about 300 guitars, and set up closer to 500. I'm not there yet.
I guess what I'm trying to say is this: having the skill set is not what makes a 'luthier'. That's what makes a luthier's employee, maybe, or a technician.
Luthierie is an art, and mastering the technique of woodworking, even on an advanced level, does not make you a luthier any more than mastering calligraphy would make you a great writer.
The difference lies in the amount of information the builder can gather, process, analyze, combine, and apply to the piece, and the extent to which they can use that knowledge to control the result.
(Bored yet? I was an English major. Sorry.)
Cheers,
Martin