"You’re an entrepreneurial developer, so why do you work for someone else?"
"You're a mechanic, so why don't you start your own garage?"
"You're a retail manager, so why don't you start your own store?"
Ad absurdum. But yes, add "entrepreneurial" to any of those and they become perfectly valid questions.
But then it really just comes down to "You're entrepreneurially inclined, so why don't you start your own business?"
"You’re an entrepreneurial developer, so why do you work for someone else?"