https://site.warrington.ufl.edu/ritter/ipo-data/
And his data shows that IPOs for the most part perform about as well as their respective market. That is large multi-billion dollar IPOs perform about as well as the broad market, and smaller IPOs (which constitute the vast majority of IPOs) perform about as well as other small-cap companies.
In other words, investing in IPOs doesn't give much of an advantage or disadvantage compared to investing in other similarly sized companies.
What's true is that most stocks, including IPOs, don't do well in the long run. The half-life of a publicly traded company is something like 10 years.