He’s rich not because of his salary (what Reddit pays him). He’s rich because of his equity/ownership in Reddit. But he can only monetize that if there are buyers.
For years this wasn’t a problem because private buyers and banks were happy to buy his shares or lend against them as collateral. However that market has been drying up over the past 18 months.
So he desperately needs to get to an IPO so he, and his Board of Directors and other stockholders, can dump their shares on an unsuspecting retail public market that doesn’t realize that the “profitability” was only achieved by destroying the user base, and that what they’ve actually bought is a ticking time bomb.