If you define capitalism as "property laws allowing ownership of capital" and further define it as "laissez-faire" meaning that the state does not use its power to promote or restrict particular firms or outcomes, then at the very least you will get the promotion of competition between industries, plus eventual limits to what a firm can do.
For example, if a monopoly in airlines leads to prohibitively expensive plane tickets, then competition from bus lines will serve as a control, and the monopoly for "all transportation types" will be reduced. Unless of course you have the airlines buying out the bus lines. But even in that case, there is a limit to how much they can charge because a new firm can enter and make a new capital investment in that industry. So at most, the monopolist can charge whatever rate would make it prohibitively expensive to enter that industry.
I can see several strategies you could use under conditions you described to maintain your monopoly if you're already big. You could, for instance, immediately buy out any serious competition before it becomes dangerous. Or, since you're a big player with deep coffers, upon seeing an upstart you could start operating at a loss an just wait until your competitor runs out of capital, and then bring the prices back up. Defeating you would require a lot of people coordinating to hit you at the same time, and we all know that people suck at coordination (and if somehow they managed to orchestrate such an operation, it wouldn't take much to bribe a participant and turn him into a defector in order to derail the whole group).
Or you could just hire a hitman. There's no concept of "fair play" in the "physical order of nature".
For example, if a monopoly in airlines leads to prohibitively expensive plane tickets, then competition from bus lines will serve as a control, and the monopoly for "all transportation types" will be reduced. Unless of course you have the airlines buying out the bus lines. But even in that case, there is a limit to how much they can charge because a new firm can enter and make a new capital investment in that industry. So at most, the monopolist can charge whatever rate would make it prohibitively expensive to enter that industry.