Those who do have a business model, outlook, and revenues that makes them attractive, like Google, can and do still IPO successfully, but there aren't many of them.
At the margin, though, SOX's costs cause private companies to delay going public, and provide a relative advantage to older/larger/already-public companies -- acquirers -- for whom compliance costs are proportionately smaller.
And since the cycle of IPOs depends on emulating prior successes, even a small initial effect could depress the follow-on rate for years.
Google is sui generis, the most successful venture-backed company of the past 30 years. If being 'like Google' is the yardstick to IPO, the system is seriously broken.
Your single-minded obsession with SOX is missing about a million other general and business-specific factors that would go into this decision, many of which represent a much higher dollar figure than sarbox compliance.
Heck, the costs of actually executing the IPO probably dwarf typical sarbox compliance costs (this statistic totally made up but plausible).