I don't think that's true. I think doing great work in the major problems in your field of choice are the exact heights that entrepreneurialism should strive for.
(Disclaimer: I recently wrote an essay arguing this same thing, for designers, for the upcoming issue 03 of Distance, which you can subscribe to at http://distance.cc/)
This essay was a turning point for me as a professional, when I found it, years ago. Entrepreneurs have the benefit of being able to look for and solve important problems in any field. And what makes a problem important? Here's how you adapt Hamming's essay on important pure science into important design work:
What makes a problem important? It’s not the end result: responsive web design provides a new way to build sites, but it’s not the only way. Rather, importance is a factor of solubility: important problems are answerable, if only you could connect the right dots. Important problems advance understanding. Marcotte figured out how to unify design rhetoric across many devices, but he probably didn’t know he was going to get there when he started in 2009: the iPad didn’t exist yet, and neither his articles nor his book mention “iPhone” or “mobile” or even just “phone” in a relevant context.
You can't know exactly what field to work in, but you can stay active in places where something might happen. Maybe these places are where the work is diligent rather than sexy – like documenting the history of interaction design, saving rare hardware, or preserving old books. Maybe they are social and cultural, like educating designers on the value of professional practices, designing supportive professional societies, and building tools for study. Or maybe the future will be built on defining best practices for future tools and their interactions. Wherever you see important problems, you’ll do great work by sharing your explorations with others.
I go on to give examples of important problems facing designers today. They're everything from how we design, to big data, to the internet of things, to natural user interfaces.
You can solve major problems in online payments, and then solve major problems in electric vehicles, and then solve major problems in space travel. You don't have to be limited by your field of academic research, and your lunch tables of chemists and mathematicians can be those of any industry in the world.
Working on important problems means your work will have long-term meaning.