While fines should be different, but in practice that line is either blurry or non existent depending on the circumstances.
For instance if Apple had to pay a global total of 2 millions of fine every year for their AppStore policy, it would be rolled in as cost of doing business and they'd keep ignoring the rulings for decades. If Amazon only had minor punishment for breaking AppSore rules they'd do it yesterday.
A binding contract is only as strong as its penalties, and in that regard we can see laws a form of contract and vice versa.
A fee is paid as an exchange of value by prior agreement. That is, you agree up front to pay the platform fees in exchange for use of the platform or specific features of it.
Fines are not an exchange of value, even if some firms attempt to treat them that way. They are also not subject to agreement. They are risk and can be arbitrary.
For instance if Apple had to pay a global total of 2 millions of fine every year for their AppStore policy, it would be rolled in as cost of doing business and they'd keep ignoring the rulings for decades. If Amazon only had minor punishment for breaking AppSore rules they'd do it yesterday.
A binding contract is only as strong as its penalties, and in that regard we can see laws a form of contract and vice versa.