As chuck McM said, start looking for a problem, rather than an idea but i would like to add this caveat:
1) Look at the background of you 3 guys, and list out problems which were being worked around in the areas of your business development or private equity or the domain of your phd friend.
There is a much higher probability of you guys having domain expertise in the areas you have been exposed to in the past, and a lot of business contacts as well - and solving a problem in those areas means that you will be able to address problems you have personally faced before - through a combination of software and services.
Note that there is no dearth of problems to be solved, but problems you have faced before personally can be a much more fruitful area for automated solutions.
A package manager is generally not part of the language per se and should not be part of the language, but rather be part of the tooling ecosystem around it. Don't get me wrong. A de facto package manager is extremely important for any major language - and it's high time someone in the C++ community builds and promotes one. It just doesn't belong in the spec.
1) Look at the background of you 3 guys, and list out problems which were being worked around in the areas of your business development or private equity or the domain of your phd friend.
There is a much higher probability of you guys having domain expertise in the areas you have been exposed to in the past, and a lot of business contacts as well - and solving a problem in those areas means that you will be able to address problems you have personally faced before - through a combination of software and services.
Note that there is no dearth of problems to be solved, but problems you have faced before personally can be a much more fruitful area for automated solutions.