I've worked as an independent for over 20 years. Sometimes with firms like SAP, Mendix, etc and other times direct with non-tech clients - usually the big corporates because they can afford to pay the best fees. Sometimes the big SIs (Accenture, Cap, etc.) get desperate and will pay well too, when a strategic account is at stake.
The fact that you enjoy speaking and writing is a big bonus!
Most experts believe their expertise is enough, which is often no longer true these days. So they fail to adopt an effective business approach to attracting clients, and are forced back into employment. Others get lucky for a while, but as with any business without a strategy to attract more business, the luck eventually runs out.
I'm running a webinar soon, which you might find helpful. Feel free to come along: http://iproinstitute.com
But don't give up your job until you've landed your first 'decent' gig or unless you have a healthy buffer in the bank. The last thing you want is to be simultaneously trying to grow your business and stressed about cashflow.