The $40.00 Wal-Mart (and other under $75.00 rods) specials have an action like a wet noodle, very poor quality guides that will groove in a short time, terrible cork (or worse a foam grip), a very poor quality reel seat, and doesn't even come with a cloth rod bag-let alone a protective rod tube.
The $150.00 Orvis Clearwater has poor quality cork, a cheap reel reel seat, comes in a thin-walled plastic rod tube, guide wraps that have gaps in them, mid-price range guides, is made on an older, less than optimum performing blank design, and has not been field tested to finalized and fine tune to final blank design.
The T&T has quality cork, high quality machined reel seat, guides of the highest quality, quality fit-and-finsh throughout, is made of the high performance modern graphites, uses an optimum performing blank design, has been field tested by several very good anglers to fine tune the blank design, and comes in a thick-walled aluminum tube with a protective cloth rod bag.
Performance wise, the Wal-Mart special cannot come close to the casting performance of either the Orvis Clearwater or the T&T in the hands of a good caster. The T&T will outperform the Orvis Clearwater in the hands of a good caster by a very measurable amount.
Now to get to the heart of your question. For the average caster and fly fisherman, a $250.00 TFO (or the Redingtons, CND Experts, and St. Croix lower end rods) will perform as well as an $800.00 T&T. So from a performance standpoint, the average fishermen is really only getting the rod tube, better cork, a better reel seat, and nicer overall fit-and-finish with the T&T compared to the TFO. However, a good caster will be able to cast farther and fish with less fatigue in a day on the river with the T&T or other high performance rod when compared to the TFO.
And there are some rods such as the Scott LS2 rods which are the top performing 2-handers in the Scott line, even though they are cheaper than the ARC's, although this is the exception in the rod world. And if a person really wants to keep his costs down while having the best reel seat, guides, cork, etc. in a rod with decent performance, he can build his own on a blank by TFO, St. Croix, Pac Bay, Forecast and have a decent performing rod with stunning cosmetics for around $250.00-$300.00 and his labor.
Me? I prefer the perfomance and cosmetics of the high-end rods of T&T, G. Loomis, Meiser, CND, Sage, etc. and gladly pay the extra dollars for them. I own 2-hand and single-hand rods by T&T, Meiser, and G.Loomis.