It seems like an ill-fitting adjective even in a vacuum, but what's worse is that "serverless" is commonly used to describe something that runs entirely client-side (e.g. p2p).
Just because AWS Lambda is a "mental shift" doesn't mean that "serverless" is a good way to describe it.
As for a better term, perhaps operationally-opaque or "pure service" are starting points? Service is correlated with stronger federation while p2p is decentralized as a rule. I'd rather avoid SOA which does not say anything about whether you have to manage the operations or dependencies - nobody is calling microservices as "server-less" after all. When people in companies talk about a "services" company they mean that the labor and overhead of management are all outsourced and as a customer you don't really care about how they operate as long as they don't violate certain OLAs and SLAs. AWS can run Lambda on marmot-based computing on Mars for all I care as long as it meets certain specs. Services compete on cost, SLAs (features are part of SLAs), and OLAs, period.