STANDSTILL agencies make money.
STANDOUT agencies make their clients money.
You can make money running an agency that builds websites, creates content and/or generates engagement in social media channels. But It can be a rollercoaster ride or even a hand to mouth existence.
There is only one sure fire way of making decent money running an agency; make your client money.
If you work directly generates profitable sales for your clients, you can charge more, retain them more easily and use the results to win other clients.