I was trained as a Mechanical Engineer and now, run a few businesses. One thing that really helped me figure out the answer to your question (which was my question too) was to take a step back from trying so hard to identify my passion or make a decision. Instead I focussed on doing a few things...
A whole lot more data is needed before anyone can answer this question. "Some people want it"...have you identified a target market? Are there similarities in these people? How many? Did they tell you what they'd pay for it? Why didn't they pay you for it already (before you wonder about this, p...