Couple of things that are either a definition, obvious, or directly observable in literally every capitalist nation in history:

• the defining characteristic of capitalism is the private ownership of businesses
• the ability to own a business can buy you influence on the electorate legally, through owning ad agencies, newspapers, think tanks, online influencers
• owning a business can buy you influence on politicians legally, by hiring lobbyists, by threatening to take your business elsewhere, by promising politicians cushy jobs after their tenure, by contributing to their campaign through fundraisers, PACs, etc
• this influence gives you the power to change laws and regulations to your benefit
• in particular, it allows you to shape laws to benefit you financially, making the actions in point 2 and 3 easier to do
• in particular, it allows you to get rid of laws restricting you to do the things in points 2 and 3
• it is in the best interest of politicians to deregulate the latter parts of point 3
• as such, a capitalist system where only parts or even none of point 2 and 3 are allowed, has a natural tendency towards a system where they are fully allowed

Leaving all other economic systems aside for a moment*, the idea that this is not a direct and natural consequence of capitalism doesn't seem to hold water, both on a theoretical and an empirical level.

(*)And we do this because, analogously, arguing your right hand isn't bleeding by saying your left hand is makes no sense. Capitalism can be studied in its own right. What's more is that the number of alternative systems is infinite, and I'm sure lemmy has a character limit.