NASDAQ lost 80% of its value from peak. That is the AVERAGE price of all the listed companies in NASDAQ. If you know how averages work, then you understand you don't get a composite drop like that without lots of index member companies losing more than that average.
I lived through it in tech. It was a bloodbath in Silicon Valley.
“NASDAQ lost 80% of its value from peak. “
You said they lost 90=99% from the pre-bubble values:
” ... when many tech stocks lost 90% to 99% of their pre-bubble value ... “