I'm re-posting this information from an Australian Forum
The reason Toyota along with some other brands are cautious is they have no control over what data Apple and Android are collecting. Android in particular collect masses of data, often without the user being aware. The other issue is control over the user experience. Toyota is keen to maintain complete control over everything the user interacts with in their models. With CarPlay and Android manufacturers give up this control to a third party. At this stage, not having these options isn't hurting sales, so there isn't need for it to be added.