Yes. Absolutely yes! In fact monopolies can not survive without government protection. The economist Murray Rothbard pointed this out. (Others have too.)
In the event of a “free market” monopoly (Actually a misuse of the word “monopoly.” According to Rothbard monopolies were originally granted by a king etc.) the colluders almost always start to undercut each other once they arrive at an agreement. Then sooner or later the cartel starts to fall apart. The only thing that can keep this medium term disintegration from happening is government.