Named-based virtual-hosting
... that's been a thing for ages. Take one large box, and resell user accounts.
On Ye Olden Days, you got shell login, email to your domain directed to your user account, and a ~/htdocs (and possibly a ~/cgi_bin) to put your applications in. No installs needed, you just used what's provided.
Extend it to J2EE/other server-platform-de-jour (~/webapps ? ) and you've got "serverless deployment" - only without the lock-in.
First bought mine in 1999.
Biting the hand that feeds IT
