And monopolies are also created without the state; just read a little history.
Discussion
A monopoly is understood as an exclusive grant of state privilege that prohibits free entry of other competitors into the market. Without legal barriers to entry, there can be no true monopoly.
With the importance of free entry into markets. If there are no laws preventing competitors from entering an industry, then even if one firm dominates the market currently, it does not constitute a monopoly in the strict sense.
Do you think Microsoft couldn't do the same if it hadn't been there?
Tell me why Microsoft, if it hadn't been there, couldn't continue buying up competing companies and closing them down as it has done for years?
Microsofts codebase could be opensourced and or copied and sold cheaper on the market outbidding microsoft by a competitor, so there would be atleast the possibility of a direct competitor since there are no gates preventing them to do so.
Of course they can buy and grow themselfs through buying competition but these are all economic voluntary decisions by the competitors to sell out to microsoft