It's not *that* far fetched. A successful software engineer can pull down $100-200K per year in the USA, and if s/he's single, it's quite easy to buy a $100K car on that kind of salary.
Err, yeah. There's not THAT many software engineers making >$100K, and if they are, you have to consider that they're certainly in higher cost of living areas and, more importantly, you can expect the number of software engineers getting paid that kind of money to decrease dramatically as jobs are shipped overseas.
There are many people who can afford a $100K car without breaking the bank. On a 5 year loan, financing $80K of the price, it's around $1500/month at 6% loan rate. Plenty of people can do that.
Plenty of highly paid doctors and lawyers, perhaps. But even then they'd probably think twice about it. $1500 a month is more than a mortgage/insurance/tax payment on a $200K house, and you think people who aren't EXTREMELY wealthy would be willing to drop that much a month for five years ON TOP of a $20K downpayment? On a depreciating asset? In an economy that's going to stay ugly for years to come? Get real. It's out of reach for a large percentage of the population.