I think this is probably a large part of it... I remember working on an app a few years ago, where it was explicit that it likely wouldn't see more than 15-20 active users at any given deployment... and with the level of normalization at the database layer, and literally 95% of the logic INSIDE the database (sprocs), it was just about falling over on a modest server trying to handle a dozen users.

Worse still, is the variance and onboarding for each customer was taking roughly twice as long as the previous one... I left during the dev cycle to bring in the 4th client. These were state/county agencies, each with slightly differing requirements. I was in charge of the UI and the API for the UI... putting all the logic inside the DB itself was emphatically NOT my decision.