Is the RNC and DNC monopolies? - eviltoast

I thought about this in response to a comment someone made and postured a position in which the RNC and DNC are really just two monopoly companies at this point (link). I know there’s protection for political parties, but is that what these really are now with how they’re structured (kinda like they’re ticketmaster/livenation for politicians at this point)? I couldn’t find an easy answer and trying to dive deeper keeps pulling up irrelevant articles.