SEO retainers usually cap your profit margins at 30 percent no matter how well...

https://bizzmarkblog.com/what-mistakes-do-agencies-make-when-they-try-to-ship-software/

SEO retainers usually cap your profit margins at 30 percent no matter how well you scale. Try treating your agency like a lab to productize your internal workflows. Shifting to software is the easiest way to push those margins past 70 percent.