As others have said, they are just in that slump.
I dont think the tax on the 4th gens is bad. My 2.0 clio is MORE. Any pre 2003 car will be on old rules.
MPG is Very good on 4th gens, especially LS1. You can get OVER 30 mpg on a steady drive, what else does that with 300 hp on tap? Better than 20 mpg if youre lucky older models
There will always be the camaro / mustang thing. Mustangs are marketed well and always have been. Plus they are in TV shows!!, camaros are not (new one is and GM are playing the game, but 5th gens not a camaro f-body anymore
)
As bigkieko said, there are a lot of 'polishers' out there. They dont know what they have as a car mechanically, they just know it shines up wel, and again the mustangs and TA's look muscular. In standard 4th gen form I dont think the camaros put up any competition really. Further more, as bigkieko knows from our discussions, I bought mine purely and simply because I wanted the fastest, most modable Yank in the running for with the best bang for buck factor. The LS1 camaro 4th gen wins hands down every time. Engine easily tunable, (ecu and mechanically wise), everything easy to swap, low service costs, engine responds very well to bolt ons, beats a mustang hands down out of the box. Can run into low 13 and very high 12's in the quarter with BOLT ONs. Heads and cam car and you have 11's already. Cant do that in a stang.
Anyway, I think I have made my point. Petrol head yanks buy camaros cause they are awesome. Regardless of generation. Thye give them a quick wash and drive them like they stole them haha
Most (not all) stang owners buy one as they look good, they are marketed as the working mans american car, and the owners can polish them and say 'yeah, i've got a mustang'
Corvette owners (most of them) are over 70 and would never go above 30 mph, they need to give their cars up and get a fiat or something crap
Ponticas are similar to corvette people, they have TAs that look like they can kick your arse, but they are too busy polishing them
(hope you guys found that funny, not being fully serious but i'm on a roll this morning
)
_________________
'99 Z28 A4, 253 LS2 heads, 228R TSP cam, Patriol Dual Springs, Double roller timing chain, LS6 ported oil pump, OBX LTs, 3" True Duals, LS6 intake, 42lb/hr injectors, SLP lid + bellow, EFIlive COS 3 Speed Denisty Tune (self tuned), 3200 Circle D stall, CAI mod, KYB AGXs, Eibach Pro Front Springs, UMI panhard, LCA + Brackets, Strut Brace, Custom Subframe connectors, WS6 axle with 3.42s, 18" American Racing Rebels, US mirrors, 93 tail lights, 3.5 inch custom cowl hood. Mickey T's Street DRs on Vette-ZR1 wheels for the strip !
Best ET: 12.0 @ 116 mph (on a 0-60ft of 1.8 s)