So, if you want to be a registrar, it is a considerable responsibility, cost, and effort. It also doesn’t solve the original problem. Users will still go to companysite.com because that’s what they think it is. Trying to tell users to go to companysite. would be damn near impossible without giving a quick DNS 101 lesson. Also, your SEO would be fuuucked. Good luck selling that to any exec. As for your concern with the Internet choosing to go with delegating domains, it’s actually critical to how we run DNS. Imagine if every single lookup had to contact the root servers. Every single email. Every single ping. Icann would have to be the size of Google. This also means that requirements for being a tld would be significantly reduced which would greatly compromise the Internet if any of them went rogue.
As someone who went to school, teachers are far from exempt from believing incredibly stupid things.