Without being involved in the industry I would imagine this is a case of supply and demand.
There are plenty of people willing to be a presenter for the amount they are willing to pay. So they get to be more selective - attractiveness is one of the most obvious things to select further on.
They could pay less. Then they'd have less attractiveness in the presenter, which hypothetically doesn't matter, and more money, which we know matters. They don't seem to want to do that.
No. The skillset for being a presenter is a subset of other skills used in business. They have to remain competitive other wise people won't work for them - there is a price floor.
TV networks seem to disagree with you... or at least place an immense amount of emphasis on finding hot presenters, for some reason.