You can also safely assume that many of the low price leaders are now on solvent printers. This cuts a huge amount of the cost for them as they no longer have to coat, and can handle the prints immediately with no danger of rub off. It's pretty hard to tell the difference now between a print on a solvent canvas with a glossy finish from a coated/matte or glossy canvas print. The newest Epson's are very good machines and have come a long way. This is of course a non-archival solution and no one yet really knows how long the solvent inks will last. They make a print that can be placed indoors or outdoors, is very durable and appears color fast.
Also, if the shop is printing on a glossy canvas without coating it, IMO you are just buying trouble in the long run. Most glossy canvas I have tried has a much more fragile top coat and in the long run if you don't coat it then you will tend to see problems down the road.
These same shops can also produce huge photo prints on traditional photo paper, that will not out gas and have sizes well beyond standard poster paper for around 25.00 a print.
Shipping is also advantageous for them instead of you, since again they have a high volume, get a better UPS rate and can buy the shipping boxes in large numbers and store them.
Also a lot of these same shops are no longer stretching with a staples, but instead using the instant wrap style bars. These hold the canvas edge with glue and can produce a very nice finished piece, and you can knock one out in 1/4 of the time on sizes like 16 x 20, 18 x 24 and 20 x 30, which is the main sizes that people seem to want.
The volume that these type of shops are printing to is simply too hard to compete with. They are using cheap labor that once trained can produce the product in a way that the consumer is happy with.
The consumer perception of printing seems to be pretty much the same as their perception of photography, i.e. it's so easy to do, all you do it connect the camera to the printer and hit print.