I think it's actually a huge number of affected people. There were at least 300K cars sold last year (based on 2018 numbers), and TurboTax is used by about (very roughly) ⅓ of tax filers. Applying that ratio to the number of cars purchased (which is a VERY rough, back-of-the-napkin kind of estimate), it's a safe bet that we're looking at closer to 100,000 TurboTax users were affected by this bug.
