Agencies often get stuck in a service loop where retainers cap margins at 30...

https://dibz.me/blog/why-a-handful-of-european-seo-agencies-stopped-being-agencies-and-1138

Agencies often get stuck in a service loop where retainers cap margins at 30 percent. Start treating your team like a lab to build software instead. Once you turn your internal workflows into a tool, those margins can jump to 70 percent plus.