Their health insurance package is extremely expensive and a huge amount of money goes into supporting campuses with buses for commuters, full meals, laundry service, and so on.

I wouldn't call health insurance "extremely expensive" in the context of Google SWE salaries. On average it probably costs on the order of $5-$10k/head/year at most. My very loose upper bound estimate is $50k/year for all aux benefits and bus/campus costs.

I'd be willing to bet something like Fuchsia is on average L5-6 (or more) given retirement projects at Google attract some very senior engineers that would offset the L3/4s if you amortize them.

nit: Stock grants/vests are not a cost to the company. They just create new shares and give them out.

They dilute shareholder value, and if you consider that many tech companies are also doing stock buybacks, it seems plausible to consider the net effect of (Handing out "free stock" with one hand) + (Buying back stock with the other hand) to be spending money.