Very much this.<p>Successful product companies (usually) have a tight integration between &quot;product&quot; people, design, and engineering. Agencies, in my experience, prefer their design teams to be buffered from stakeholders via a PM.  And the &quot;stakeholders&quot; are a very narrow segment of the team building the actual product. As an engineer, I struggled getting face-time with designers to work through challenges or things that were unaccounted for. Often times this was filtered through the design firms PM, who would maybe get back to me in a week or so. It was always an excruciatingly slow process and unless you were the one signing the checks it was like you did not have a voice.<p>Then there&#x27;s the fact that agencies do not like something that&#x27;s quite popular these days: Metrics-driven product development. I know certain &quot;thought leaders&quot; in the design community have made some sneering comments about this approach. Metrics don&#x27;t exactly get me super excited, but if that&#x27;s how your customers are working you should learn how to adapt and work with them.<p>I worked at two companies that made the transition from agency to in-house. Shortly after we brought on our first designer, productivity went up. We shipped stuff that made our customers happier than ever. Team morale improved. And it was cheaper. Win-win-win.