The investors lose. The companies are liquidated and the assets bought by new investors. This actually happened to GM, to a degree. The workers don't have to lose out.
Realistically speaking, it's far more likely that in an established industry like autos the cheating company will simply beat their competitors at market because they can sell cheaper, spend less on research, etc.
It's nice to imagine that maybe it would breed "super companies" that are tougher, smarter, and more efficient because they thought they had to be to compete. But, there aren't any order-of-magnitude wins to be had in automobile technology. There are no lone geniuses who figure out how to eke out 10% more efficiency with this one weird (but patentable) trick. It takes research over a long period time to make even modest gains, and a cheater in the market bleeds the honest companies of resources.
And, to go further: Because Volkswagen made these claims about diesel tech, other honest companies may have been wasting resources trying to match the dishonest VW claims...when there are actual better techs they could have been pursuing. This may have led to even less gains over the time VW were faking data.
Consumers also lose out, because of decreased market competition.