Camera lucida again

I got into trouble - I can handle it: big, tough, 'orrible that's me! - a while ago when I referred to David Hockney's book on this subject as "bad".  It wasn't only Hockney, I've forgotten his co-author.   An advertising post on Facebook will show you WHY I disparaged it.  It refers to a thing called Neo-Lucida as "the secret tool of the old masters" - and that is just complete and utter rubbish, and what happens when artists dabble in speculation on subjects of which they know nothing, but guess much.  Or rather, when their arguments are called in aid by those who want to sell us something.  I don't think David Hockney has ever pretended that he KNEW; he was innocently speculating, and that's fine (I know David will SO appreciate my defence of him).  Quite possibly, many artists used the camera lucida and other optical devices: I don't know - I'm getting on a bit, but I wasn't around at the time.  Equally possibly, the reason they are called old masters is that they WERE masters: they could draw without external aids.  I wouldn't dissuade anyone from using such devices if their drawing gives them trouble, we've all struggled with putting our vision on paper, I don't despise aids to doing so.  But when this turns to flogging product, I do get very cross - because you might not need it; you might find that practice helps you to get where you want to be; no shame on you if it doesn't, but do at least TRY to draw without aids, because if you think you can't draw without them, you almost certainly can, if you keep doing it: don't accept that you can't draw and must have this piece of equipment.  You learned to write without aids - even if some seem to have forgotten thanks to emails and ready access to a whole world of fonts!  You can learn to draw without them, too. Can we not just kick the quick-fix and instant solution out of the way?  Must we be dictated to by the techno-short-cut?   Told you it made me cross......