I agree with a lot of this.
I think both DeLorean & Bricklin, as companies, didn't have enough work done in design of the car or the production process, or enough money in actually building the cars: that is, the basics were good, but parts fit-up a bit haphazard because there isn't good enough design in the tooling/manufacturing or enough money in the process. It goes beyond bad quality control: GM can fix these problems on the line, because the line is built right to fix it; it seems to me DeLorean & Bricklin never had a hope of fixing it, because their production processes were too badly engineered.
Tucker had that in spades.

Some of the engineering decisions were downright nutty: converting from aircooled to watercooled?

The preselector trans wasn't ideal, nor adequately debugged. Building in a former B-24 plant, which was far from ideal for car-building, wasn't really a good idea, either.
That said, when you say "survive", would you accept having the cars produced, but not the companies created? The prospect of a Tucker-designed sedan at, frex, Kaiser in '47-8 doesn't seem unreasonable. Nor a DeLorean at AMC, in place of the AMX, or a Bricklin as a Corvette competitor at AMC or Chrysler.