This is an interesting thread. It certainly shows the different attitudes that prevail in our hobby. I am not disagreeing with anyone at all.
As far as the cost of 3d printing goes ... I have had one for a couple of months and I am nearing the 200 or so hours on it. It took near enough to two weeks to get it dialed in to the point where I can start a print, and leave it to it, allowing me to work on the mill or lathe, or go for a swim.
My friend owns a pet store that specializes in aquariums and reptiles. You guessed it ... soon as he heard I had a printer, He wanted stuff printed. Simple things like little perforated trays for starting plants on. Nothing to it, right! First prototype drawn up and printed ... 2 hours. Not quite right so revise the drawing and reprint. Better, but no cigar, even though it was exactly what he asked for. Third iteration of said shelf ... perfect, but not quite good enough quality, so I reduced the extrusion thickness ...
The long and short of it is that he can get what he needs from regular distributor for $1.50 and wants to cut that cost. He wanted to pay me $1.00 each and he wanted 100 at a time. My printer will do 9 at once at the size he wants, but at the quality he wants, that takes 4 1/2 hours per 9! Do the math and I would be printing for a long time to fill the order. I politely declined the business, gave him the samples that I made, and decided that a commercial venture as a 3d printing firm is not on my cards.
In my humble opinion, the fellow doing the wipers was losing money.