sounds like big tech shouldn't have spent the last decade investing in a kitchen refit so that they could make stew really well but nothing else

If there's something illegal in your dish, you throw it out. It's not a question. I don't care that you spent a lot of time and money on it. "I spent a lot of time preparing the circumstances leading to this crime" is not an excuse, neither is "if I have to face consequences for committing this crime, I might lose money".

Replace salt with poison or an allergenic substance and if fully holds. If a batch has been contaminated, then yes, you should try again.

But now that the cat is out of the bag, other companies are less willing to let something be scrap able due to how valuable it can be.

I think big tech knew this, that they can only build these models on unfiltered data before the AI craze.

It will probably be way shittier without all the private data they put in the first time too.

I work in this field a good bit, and you're largely correct. That's a great analogy of trying to remove salt from a stew. The only issue with that analogy is that that's technically possible still by distilling the stew and recovering the salt. Even though it would destroy the stew.

At the point that pii data is in the model, it's fully baked. It'd be like trying to get the eggs out of a baked cake. The chemical composition has changed into something else completely.

That's how building a model works today. Like baking a cake.

I'm order to remove or even identify pii data in ML models or LLMs today, we'd need a whole new way of baking a cake that would keep the eggs separate from the cake until just before you tried to take a bite out of it. The tools today don't allow you to do anything like that. They bake you a complete cake.

Something to take in mind is that yes, they would need to retrain the models from zero, but if they did it in any kind of basic decent method they should have backups and versions of the data they used to train and they would need to retrain everything with a subset of the original data. Then, the optimizations they have already applied to the system should be able to be reapplied in the same manner and the product should be somewhat similar. Another thing would be to design a de training process, where you generate an input from the "must be deleted" input that when trained acts as some sort of "negative input" and the model ends up in the same place it would have ended up if it were not trained with the "must be deleted" data.

I bet you that if governments act harsh enough tech companies will develop some sort of "negative training".

In the end this is a solvable math optimization problem, what input do I need to feed the already trained model for it to become the equivalent model it would be if trained without the requested data.

We could even create an ML model that computes a "good enough negative input" from several examples, since testing the quality of the results is quite simple, and we can train it with several trained model examples. This model would be fed with a base model, some input data and another base model trained without that data.

All in all, AI companies will tell you that this is very hard because they would essentially be investing hours and development to create a tool that makes their model worse instead of better, so expect a lot of pushback.