Any company using the massive amount of bandwidth you are thinking of is probably not getting all the features required for their business on the $20/month plan

Any company using the massive amount of bandwidth you are thinking of is probably not getting all the features required for their business on the $20/month plan. Hell, you can't even obtain access logs without the enterprise pricing. Your limit won't come from CloudFlare restricting you, a lack of basic necessities from the product will have you crawling to pay whatever enterprise amount they want.