1 good ongoing client is better than 100 one-off projects with different clients.
There's a huge overhead to finding and onboarding a new client/project. Instead find one good ongoing contract, and put all your extra energy into creating a product that can scale.
Freelancing is a dead end road, but you can use it as a tool to bootstrap your own lifestyle business.
see also: Four Hour Workweek and Start Small, Stay Small
I mostly agree with you, except much of the freelancing allure stems from working on new and exciting things, avoiding burnout and boredom. So I'd modify that statement to:
3-4 good ongoing clients is better than 100 one-off projects with different clients.
Edit: didn't read the last half of your comment. If running a startup or building a product is your primary goal, then I absolutely agree with you.