That's cheating.
Any time I see a car with exhaust dumping out in front of the rear wheels or ending at the rear axle, I get the impression that the guy cut corners there and probably a bunch of other places as well.
There is probably a great deal of truth in your opinion/statement. My Caballero is, and always has been, a regular driver. When it was down for an engine and transmission transplant, I wanted it back together as quickly and inexpensively as possible. I chose to have my exhaust dump out before the tires partially because the shop said that they would have to put a small crush in the pipe as it passes over the axle. I did not want any restrictions to the exhaust flow, so ahead of the tires it went. It did save me a few bucks, but I could have afforded it, and it would not have taken any more time.
As far as cutting other corners, I reused the original bellhousing, flywheel, and even the clutch and pressure plate. Three years gone, and so far all is well.