The build went well. Custom design, clean Webflow, Lighthouse in the nineties, the client cried a little on the handover call. Six months later you look at it for a portfolio screenshot and the blog has two posts, both from launch week, and the case study you wanted to write is a site nobody visits.
The part that actually bothers you is that you knew this would happen and you had no answer. They asked who would write it. You said you could recommend someone, or quote a retainer, and then you did the maths on subcontracting at $300 an article and realised you would be running a content desk for a few hundred dollars of margin and all of the blame.
So it becomes a project business forever. Every January starts at zero, revenue is whoever signed a build that quarter, and the recurring line that would make the agency worth something on a balance sheet keeps not existing. Meanwhile your own site — the one you would judge a client for — has a blog with three posts from 2023.
And the client who churned to a competitor last spring did it because that agency answered "yes" to the content question.