> On other side the companies should then be able to sue you

Companies can sue you for false, damaging claims you make, or failure to complete your end of a contractual arrangement.

> and you need to prove that charge was fraudulent

Well, no, the initial burden of proof should remain on the entity seeking a remedy, but civil standard of proof (preponderance of the evidence) means that that initial burden is not hard to meet.

This is really how the system works in most places. If a chargeback result is unjust, the merchant can sue. In most places court costs and attorney fees are awarded to the winner. Most of the time, merchants just assign the account to a collection agency after 90 days and hope for something.