ANYONE can delete unsourced or improperly sourced material.
"Yes, welcome to delete the false information that we're publishing about you/your company. Oh, you work for that company? Let the ban hammer sing!" COI (Conflict Of Interest), i.e. someone editing an article where they have a stake at play, often means in practice that the user is banned within microseconds, if there are any anonymous editors with differing opinions. The guideline page itself says "Paid advocates are very strongly discouraged from direct article editing, and should instead propose changes on the talk page of the article in question". The admins have even set up a noticeboard, where anonymous editors can report people they suspect of having "COI".
In short, if people would _follow the fucking rules_ that Wikipedia has made fairly clear, they could edit their own articles as much as they pleased.
This is classical Wikipedia style arrogance. What you are essentially saying, is that Wikipedia will default to publishing blatant misinformation and propaganda added by anonymous and/or pseudonymous editors with impunity. If you happen to disagree with a mispresentation of your person, your company or your product published through Wikipedia, you must jump through numerous hoops and face the newcomer-hostile "Wikipedia community", who will first demand you read through several 10+ page guidelines, manuals and policy discussions. Then, you will need to contact an admin, who might live on a different timezone, to have the page actually modified. And you had better declare your COI on your user page, too. There might be other hoops to jump through as well – just for clearing lies and misrepresentations published on Wikipedia that happen to concern you. And if you at any point make even the slightest of a mistake, you and your whole company (under the "sockpuppet rules") are easily banned from Wikipedia forever.
Why would any sensible person who has better things in life than reading Wikipedia manuals and guidelines ever even try correcting the pages? The hostile and self-proclaimed meritocracy make Wikipedia a truly kafkaesque experience to all outsiders who don't happen to be wiki-nerds or willing to become one. Paid editing, exactly what Wiki-PR seems to have been doing, would be the easy way to make Wikipedia more neutral by allowing companies to hire editors to remove at least some of the blatant propaganda that Wikipedia is currently full of.