Apple records and keeps users' Siri queries for up to 2 years

It does not need to be personalized, it only needs to be associated with a given data set. How it's applied to the personal device in question is an implementation problem, not a matter of whether anonymization should have been implemented.

Presumably. Google even desires to keep the data personalized if you opt in and allow them.

So, you're right that no one knows something like that. However, I think that Apple and Google (to use two specific companies) have very different approaches to gaining their profits. Apple tries to roll out higher-margin devices and get you to part with your dollars to buy it. Google, on the other hand, tries to roll out free things and get advertisers to part with their advertising dollars, serving you up as the product. That sounds a little more anti-ad than I mean it to, but I think it illustrates the "if you aren't paying, you're the product" point. There's nothing wrong with being the product if you get something awesome in return. Gmail is awesome and free.

However, once you're scanning emails for targeting an ad specific to the email, why not try to build a profile of a person? Why not try to figure out as much as you can to target them? With a mobile device, why not track their location (linked to an account) so you can tell where they are usually going? Build their voice queries into that profile? Now when they walk to a certain area and it's tuesday near lunch, maybe you know what restaurant they like and serve an ad for a competitor.

Again, some of this is hyperbole to illustrate a point and I'm not accusing Google of anything. But Google makes its money off of being able to sell ads that are relevant to you. They try to keep it to a non-creepy level, but it's their profit engine. Apple, on the other hand, makes their money off you from getting you to part with your dollars in exchange for one of their shiny toys. In fact, when you look at Apple's revenues, only 3% come from sources other than the iPhone, iPad, iTunes, iPod, and computers. Unless Apple wants to dramatically change course, the data is much more likely to be used for improvement of the system rather than targeting of individual users.

That doesn't ensure that your data will be used in any fashion by any company. But I think Apple's revenue streams show that, at least right now, they aren't heavily into any area where targeting you via these recordings would be useful for them. In fact, if anything it would jeopardize their already highly-profitable operations and that would make it a hard decision to exploit it.

I can't speak for the parent, but this is my reasoning: They make close to a hundred billion dollars a year by selling hardware, so they don't need to sell my private information for some quick cash.

It's stupid, I know. But the same couldn't be said about advertising-driven companies (like Google and Facebook).

In other words, being mindful of user privacy is a luxury they can have right now, and it's good for their business (i.e., they're not doing it because they're "good", or others that do are "bad" or "evil" - it's just that they're now in a position that respecting user privacy is better for their bottom line than not being respectful)