Why can’t we say Je voudrais proposer un toast instead of je voudrais porter un toast?

In English, there are many ways to 'raise a toast', depending on formality of the setting. In France the formal expressions when toasting are «portons un toast» and «levons nos verres». Obviously there are also informal ways, but even though they may fit on a word for word translation «proposer un toast» or «offrir un toast» are not amongst them.