The stock value didn't drop because of CUDA but because most stocks and tech stocks dropped in 2008. AMD was also down 80%, Intel down 40%.
But then I realized the author might have been a toddler at that time so might not have lived through it, making it easier to forget.
How time flies...
[1]: https://en.wikipedia.org/wiki/2007%E2%80%932008_financial_cr...