I'm not the guy you're asking, and you didn't need to be rude, but the difference is a fun driving experience. It's perfectly OK not to value that, but it's a valid priority.
I'm speaking here as an NA Miata owner. My car's waaay behind your Prius on the luxury scale: it's loud on the freeway, and rattles and bumps the whole time; there's no cruise control; the roof seals leak a bit if you don't close the windows / doors in just the right way; the AC's on the fritz at the moment, and I need to sand off and re-spray some peeling clear coat that makes it look dumb. I've put more time (and actual $$) into the car than its paper value should justify, but goddamn does dropping the roof and pulling out of the driveway put a silly smile onto my face every single time, and heel-and-toeing a downshift on a twisty road to hit the next corner just right never stops being a thrill.
"Upgrading" to a more expensive car would buy me the luxury and the fun together - together with a lot of engine power I don't need outside the track, and would frankly be scared of day-to-day - and (to the point of this thread) I'm kinda frugal, so I don't feel any need to do that. But "luxury" (even "comfort", sometimes) and "fun" are orthogonal values, in the automotive world, and you asked, so that's the answer.
I'm not convinced there's a materially more-fun driving experience to be had by spending gobs more money.
If you optimize for that instead of other aspects, then Prius money would get you a Miata with most of the same features and a sportier aspects. And you're still a long way from a six-figure car. That was the gist of my earliest point.
I think the gist of your point got missed by both me and the GP. It read like you didn't think / understand fun was any kind of a value at all. I mean, you did ask:
> What specific benefits does a "driver's car" have over a "regular" car, praytell?
You're dead right on about the Miata vs Prius comparison, though. If I wasn't, for all of its manifest inconveniences, unreasonably in love with my (at this point classic status) little car I'd "upgrade" to a newer Miata.
That said:
> a materially more-fun driving experience [isn't] to be had by spending gobs more money
Kinda isn't the case? I've driven a couple of $100k+ cars, and they were a fricking blast. Effortless power is intoxicating; you feel momentarily like a super-hero when you put the throttle down. I can only imagine that a proper racecar is another leap beyond that - albeit with a massive decrease in comfort.
The catch, however, is that you can't safely (or legally) drive high-performance cars anywhere near their limit in public, only on the track. So, 99% of the time 90% of the money you've spent is wasted. My Miata is 90% of the fun 100% of the time, at (mostly!) legal speeds, and if I want to actually push its / my limits I can do that on a cone course in an empty parking lot, no track required.
(Also, little kids smile and wave at me all the time, because it's cute, and hard-core gear-heads start conversations with me about it at petrol stations. That's all fun, too.)
I think I'm getting a lot more enjoyment per dollar or per mile than the $100k+ fools do.
Unless, of course, they're doing it for status signaling, which they mostly are. That's fair, I guess; I don't think my Miata ever got me laid, which (I'm told) their cars do. The rest of us just wish they'd be damn honest about it, that's all.
The thing is all 100k cars are well past the point of diminishing returns.
I use to have a 993. It was a lot of fun. I also had a 2016 GTI. It was at least 85% of the fun for 20% the cost. It didn’t turn heads as much, though, which is what most people buying high end cars are after.
These days I get my zoomies on two wheels. I have a Triumph, so I’m very familiar with the gas station chat-ups. ;)
I'm speaking here as an NA Miata owner. My car's waaay behind your Prius on the luxury scale: it's loud on the freeway, and rattles and bumps the whole time; there's no cruise control; the roof seals leak a bit if you don't close the windows / doors in just the right way; the AC's on the fritz at the moment, and I need to sand off and re-spray some peeling clear coat that makes it look dumb. I've put more time (and actual $$) into the car than its paper value should justify, but goddamn does dropping the roof and pulling out of the driveway put a silly smile onto my face every single time, and heel-and-toeing a downshift on a twisty road to hit the next corner just right never stops being a thrill.
"Upgrading" to a more expensive car would buy me the luxury and the fun together - together with a lot of engine power I don't need outside the track, and would frankly be scared of day-to-day - and (to the point of this thread) I'm kinda frugal, so I don't feel any need to do that. But "luxury" (even "comfort", sometimes) and "fun" are orthogonal values, in the automotive world, and you asked, so that's the answer.