Anywhere you have a free-rider problem, government and public investments are usually a better solution than private enterprise.
The primary industries where this is the case are:
Police & Defense
Roads & Bridges
Air Traffic Control
Savings Deposit Insurance (FDIC)
Everything else should be left primarily to private enterprise. The problem with a devotion to Reagan's old saw, "Government is not the solution to our problem, it is the problem" is that it often translates into the belief that government should only do the first item on the list above.
And, if you think government should do practically nothing, you mistakenly believe that those of us in the Democratic Party believe that government should do practically everything.
What if I told you that I and most Democrats believe government is about the right size, we just need to pay for the government we have? Would you believe it? Why not?