The SDR calculation [1] excludes compensation and looks like a generous net revenue measure. Earnings per share -- from which P/E multiples on public companies are typically calculated -- includes compensation, interest expense, various non-cash adjustments, and adjustment for dilution.[2] Generally you would expect the SDR number to be higher than net income and correspondingly attract a lower multiple in estimating firm value.
As others have commented, there are additional reasons why valuation metrics for large-cap listed companies don’t make for useful comparison with SaaS startups. See also Heidi Roizen’s cautionary tale [3] about the perils of multiple envy.
[1] https://news.ycombinator.com/item?id=9589223
[2] https://en.wikipedia.org/wiki/Earnings_per_share see also ../Net_income