I think the dot com bubble was the most damaging. Prior to that IPOs were not something the average investor would try to get in to. First day "pops" were modes

I think the dot com bubble was the most damaging. Prior to that IPOs were not something the average investor would try to get in to. First day "pops" were modest and the expectation was that a company (even a tech one) should have 8 quarters of steadily improving profits prior to the offering.