All time? All time? you expect me to choose one for ALL TIME?
Well, doo on you. I'm choosing two, and neither are on the list. Neither make cars anymore, either, but you have a few orphan makes on there, so....
American Motors
Studebaker-Packard Corporation
AMC
What would you do if you had to compete with the Big Three? That was often a tagline in '60s and '70s AMC ads. If you're AMC, you think of clever ways to overcome your revenue disadvantage.
In the late '50s, AMC produced one of the first American subcompact cars, the Metropolitan. The engine was a British Rover engine, the kind you might see in the Morris Minor. Styling was attractive, and the car actually sold reasonably well.
AMC always did their best in the compact and subcompact market. From the reliable Rambler lineup and the later Hornet and Gremlin lines. The Gremlin, in fact, was one of the most successful domestic compact cars - it was a reliable machine in a field of engine-grinding Vegas and exploding Pintos. There was also the similar, and quite useful, but perhaps a bit-too-ahead-of-it's-time AMC Pacer.
Moreover, AMC looked for any niche they could fill. Hothatch? Stuff a 5-liter V8 in a Gremlin, YEARS before VW's GTI, or the Vauxhall Chevette HS. Sport-utility capability with Car ride? Lift an AMC Spirit and give it shift-on-the-fly 4WD. Call it Eagle. Create the crossover field singlehandedly, and predate the BMW X6 by 20 years.
And, we will all remember the Javelin and AMX, those most potent Ponycars, and we still have the Jeep. In fact, we still had AMC's Six until a few years ago!!!
Studebaker/Packard
I haven't a clue why these makes didn't survive. Well, I have an inkling, but...well, they didnt' deserve to become lost forever.
Simply put, despite making some of the finest cars in the US, they were run by idiots.
Packard, for example, had quite the modern engine at the time of it's takeover by Stude. In fact, the Packard could easily go toe-to-toe with midlevel Oldsmobiles and Buicks and leave with it's head up high (probably easily, given how GM was at that time) It's engine came late to the party, though, but it still may have succeeded.
Studebaker was even more radical. Factory supercharging is common nowadays (although it's usually an exhaust-driven turbine,) but in the late '50s and early '60s, it was nigh unheard of. Sure, some ridiculously expensive pre-war cars had blowers, and kids were taking the superchargers off of Detroit Diesel trucks and throwing them onto just about every GM, Ford and Chrysler mill imaginable. So staid old Studebaker, throwing a blower onto their automobiles, was a surprise. It was a shame the cars weren't allowed to compete more in factory racing like NASCAR.
Not to mention the designs that Studebaker produced are forever and always classics, strikingly beautiful. The man who created them, Raymond Loewy, also penned the Pennsylvania Railroad's streamlined locomotives, and Baldwin's "Sharknose" Diesels, so it was logical that his cars would also be quite striking...and they were. I absolutely adore the Hawk and Avanti's looks...just so much more streamlined than anything else of the era, and so different. The Avanti could even be an early '70s design.
It's sad, then, that the company was so mismanaged. I'd like to have seen what would happen if they'd had a fair chance.
Yes, I know, I could have just as easily chosen Chrysler, but my disgust of the company (and it's recent aquisition by FIAT) Has me a little miffed.