This is an incorrect assumption that is true of ETH, but not the majority of coins that Coinbase Earn ingests.
From the 10-k:
We operate staking nodes on certain blockchain networks utilizing customers’ crypto assets and pass through the rewards received to those customers, less a service fee. In other cases, upon customers’ instructions, we may delegate our customers’ assets to third-party service providers that are unaffiliated with us. Some networks may further require customer assets to be transferred into smart contracts on the underlying blockchain networks not under our or anyone’s control.
>The risk profile also isn't exactly comparable, as in your example the bankruptcy and the potential profits are directly linked, while slashing is a punitive measure imposed by the protocol to punish bad behavior.
What? Do a good job, make money. Do a bad job lose money.