Stable job prevents me from making more money

I realized just recently that my stable well-paid job (software developer) is actually preventing me from making more money. I red somewhere that if you get paid by the hour it will take you a lot of time to get very wealthy.

For the next 2-3 months I'm bound to the project, but I'm thinking if freelancing wouldn't be better for me where I'm paid for results rather than time and develop my own apps.

How would you guys approach this?

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