I cannot disagree with you more.. Miata, Nissan's 240, The Supra, even the FWD Prelude - all have amazing resale value.. and none of them are practical. My experience tells me that cars that hold value best are the ones people *WANT*, not the ones that make sense.
The Miata is a staple and always has been. The only reason the 240 is popular is because of drifting. The Supra is a god in the eyes of tuners. Plus it was SUPER cheap to buy a 93' Supra TT before Fast and the Furious came out. After that they have bounced up in value.
The Prelude is good for its time but I suppose there isn't much call for it here. I haven't seen one on the road in a LONG time.
The FR-S and BRZ are caught up in the "Genesis" craze. The Genesis Coupe sold like crazy here but they did not hold their value well at all.
The FR-S and BRZ held their value well at first because dealers were over sold. Now they are a dime a dozen. When that happens the value plummets.
The hot hatch is a car that appeals to a much larger market where the sports coupe is a niche market.
The reason a GTI sells so well is because your Mom, Dad, Girlfriend, Boyfriend, Brother, Sister, Cousin, Neighbour, Teacher can buy it because it serves it's purpose to everyone. It is a posh Golf for your mom, it is a pocket rocket for you and your brother and dad. It had a trunk for your sister and her kids.
The sports coupe is a great car and some people can justify buying one but not nearly as many people as can a hot hatch.
The ST is made in a relatively small batch, it is quick and everyone who gets near one loves it. It will hold its value very well. The FR-S and BRZ will become the Genesis once the hype wears off. Great cars but just cannot fit as many lifestyles as a hot hatch.