Earlier quoted context omitted.
Yeah, they said its "serverless" but it requires an AWS lambda function. I use Jekyll for my blog but I simply commit, push, and run a script that copies the files to S3. https://www.tberra.com/aws/amazon/meta/2016/11/12/the-birth-... its not scheduled but I could easily tell linux to run that command once at whatever time I wanted.
AWS lambda functions __are__ serverless. There's no notion of uptime, provisioning or managing servers when using lambda.
There's no notion of uptime, provisioning or managing Web sites when using Web sites; but the operators of the Web site certainly have to tackle such things.
Likewise, I'm sure the operators of AWS lambda are very much concerned about such things, even if the users aren't.
In that sense, wordpress.com is "serverless".