Entering markets with big existing players, high barrier to entry

I think about what I like building and doing, and what markets I might be able enter, and they all seem to be ones where big players exist because there is a high barrier to entry (expensive infrastructure investments needed, manufacturing connections needed, heavy government regulation, etc). Not exactly something you can tackle on your own with a macbook in a starbucks, at least I don't think. What course of action should one take to break into this kind of scene? Right now for the time being I'm working at one of these big existing players and trying to learn their processes as best I can. But when I think of branching out and starting something on my own... I guess my resourcefulness isn't yet at the level it needs to be. I know I didn't mention any specific industries. As a successful example of this, I think of a company like Stripe. Handling credit cards? How the hell? Good job. As an example where I don't know of any small new players trying out, how about telecommunications. Letting people call each other. Or providing internet to people. Best I know of for those two are smaller companies buying whatever bandwidth they can from bigger players and then trying to manage it on their own and do better. Thoughts and advice?