Important to note that the Silver Consensus doesn't exist.
The 'full' version in Transforming Mythic Europe is an example of what it could be, not what it is.
The Stonehenge consensus specifically mentions silver; no other wealth generation mechanism is covered by the Stonehenge version.
The reason for the more complete version is because magi aren't idiots, and the more complete version is a pretty good example of what would probably be proposed at Grand Tribunal.
There is another couple of things to point out:
Some covenants are getting their wealth through magical means, and having the silver consensus come into play will deny them their wealth. This includes very well established covenants who are simply better at laundering their money than whomever the Stonehenge ruling was created for. These covenants are going to want to protect their income.
In addition, the Silver Consensus is self-policing in other tribunals even without a GT ruling. Enough magi are aware of what happened in Stonehenge, so they're going to want to avoid having the same hammer fall on them. Thus, any covenant that starts making silver or inordinate wealth via obviously magical means is going to get the more established covenants in the area taking steps to stop them. Wizard's War (or the threat thereof) on some junior covenants is far less bother than politics in Grand Tribunal.
Finally, the entire ruling as presented smacks of an isolationist order, which brings certain other political arguments to the fore. It's a move that is probably going to gain support by wilderists and traditionalists, but be fought by transitionalists and harmonists... and almost all of House Jerbiton and House Verditius. Ironically, House Tremere isn't going to be financially effected by the outcome either way, so they're going to be voting from ideals instead of survival.
So while the ruling as presented in Transforming Mythic Europe is certainly an example, I would say it is very much not a foregone conclusion that this is how it's going to play out, or that it is going to be a whitewash.
In fact, unless the group who are pushing for a GT-level ruling on the matter have been very politically active in gaining allies and preparing the field, I'd suspect such a motion won't carry. They might be better off trying to roll the ruling into neighbouring tribunals' peripheral code and worrying about GT in another 40 years.
It certainly wouldn't apply retroactively, but whether it is allowed to apply to existing income sources that already use magic is something that would have to be discussed. That's super contentious, because there's going to be some big Autumn covenants who would be hurt by that one.