Stick to one genre?

Writing is a business as well as a passion. When I put on my business cap, I know it is best to write in one genre to gain a following of readers. I also know series sell.

I can't seem to settle on a niche, but maybe I should. I have WIPs for a historical and a timetravel. I love both stories passionately. I also have an outline for a contemporary suspense and a concept for a 'small town' series.

I am writing as fast as my life (job to pay bills, family that likes meals and expects interaction, sleep when my eyes water and blur) allows. I know I am a chronic debater of all sides of any issue (from word choice to this choice of story to focus on.)

Do I need to be locked in a box (with laptop) until I choose one genre and publish X number of published books in that genre before I tackle the others? I do love the act / art of writing.