Ask HN: Technically interesting vs. a good business

If something is technically interesting is it likely to make a good business? How do you balance between doing what is technically interesting, and what is profitable?

If you have some tool to make programming 10x more efficient, do you have business, or just an open source project? Meanwhile, if you have a new way to do e-commerce, you may have the Groupon?

In the current environment, is pure tech devalued while everyone needs good, simple technology? As a hacker do you focus on building tech or a consumer business?