The only way you can guarantee that you'll still be running your freelance business in a year or two is by making yourself as valuable as possible to your clients. But what makes you valuable?
You aren't valuable because of your experience. You aren't valuable because of your competitive rate of pay. You aren't valuable because of your connections.
No, freelancers become valuable to their clients by doing one simple thing: solving their problems.
Learn to offer the right solutions to your clients when they call for help. That's how you become indispensable. That's how you build a career that lasts.