Monolithic apps running on big servers talking to databases running on big servers. Very little orchestration overhead or complexity with serverless and the rest.
Everything from StackOverflow to ad serving systems to high-frequency trading exchanges are run this way.
What is your definition of non-boring architecture? I'm curious as to what you consider the exciting architectures necessary for scaling to make sure we're talking about the same thing.
Quora, Pinterest, Twitter, etc are all just big app instances talking to DB instances, with separate systems for background processing, queues, and caching. Are you suggesting that they would scale better with serverless functions instead?