This is such a simple solution. Before two years replace for free, after two years, just inform user battery is inadequate. Offer battery management windows style which includes user selected throttling. After two years, a deprecated battery is expected and nobody will complain about shutdowns. Replace battery or implement power management.
The longer Apple stays silent on this, the longer the damage to its brand. Everyday, there’s a lawsuit and the EU didn’t even get involved yet. Even if Apple loses all the lawsuits, the damage will not outweigh the damage to its brand. That will seriously cause financial damage.
If Apple think staying silent and waiting for the masses to forget throttlegate, Apple is sadly mistaken. As times goes by, more and more users batteries will degrade and throttlegate will magnify. Come clean, pay up, make the fan base happy again.