I’ve been involved with two designers that have become entrepreneurs and eventually released products that have formed a business.
Both of them came from personal projects they did in their evenings and weekends, identified a problem and then designed a product from them. Then they realised people would buy this, one went the Kickstarter route and one went the angel/VC route. Both are doing very well for themselves and one of them now has a full-fledged start-up with a staff of 50 and just received $10m in a series B round to progress further, as well as being profitable. The other reached £1m on crowdfunding as is off to China every other week whilst tools are made. He has enough in the bank that him and his wife plus a freelancer or two can keep the bills being paid.
Long story short, have an idea and a product, put it out in the world and voila, you’re an entrepreneur.