Apart from the fact that they have no incentive to, there are technical downsides, even assuming you could get a useful homomorphic scheme to work in practice.
For example, encrypted data can't be compressed. Columnar big data systems rely heavily on that to be performant.
> Apart from the fact that they have no incentive to
They have huge incentives. Apple is positioning themselves as the privacy king. Meta has suffered huge losses because of their privacy abuses. Neither of these suggest no incentives. I'd argue that they suggest large incentives.
The technical downsides are a fair critique though. But this also is where competition excels. Our machines are getting faster. Other algorithms have also gotten extremely faster and it would be naive to assume that homormorphic algorithms similarly don't. This is why I say an arms race.
Apple has done plenty of major screwups that each put a big doubt on whether “Apple loves your privacy” is something more than PR BS, but for some reason, they all got memoryholed.
An iphone user is _probably_ tracked by less ad agencies than a stock android user, but that’s it.
> They have huge incentives. Apple is positioning themselves as the privacy king
I am willing to bet that it is a deal breaker only for very small minority of users. I would argue that search engine data is of much bigger privacy concern than OS, as compared to search history no OS action comes close in disclosing personal action, and google/bing almost has universal market presence even for Apple users.
> Meta has suffered huge losses because of their privacy abuses.
They had their revenue reduced, true. But it is not loss. They wouldn't be in any better position if they didn't used extra data when it was available.
I wonder if there's new feature or improvement Apple could introduce that would actually increase their sales. It seems like at the moment people buy the new iPhone because 1/ they need/want a new phone, 2/ they want an iPhone, and 3/ they want the new iPhone.
Apple know what they need to do to be successful, and that's continue to release updates to the iPhone that in a few small ways make it slightly better than the previous one.
The other thing is you could likely squeeze your competition out of the market. Countries are waking up to the implications of data harvesting and that it isn't only being used by themselves but their adversaries. So if a big company, like Apple, got it working, it would be much easier to lobby legislation that would harm (or kill) your competitors. (While I think we would all be better off if this happened, I do recognize that this same power can be abused and cause a significant disruption in the ecosystem. But I think it would also be extremely difficult to impossible to gain such an edge that others couldn't quickly adapt. Even if they drag their feet)
For example, encrypted data can't be compressed. Columnar big data systems rely heavily on that to be performant.