[manuelabeledo]

> They protect their product lines from each other.

Is that the case, though.

Their product lines overlap significantly in several areas. Yes, you cannot use the Phone app in an iPad, but you can do many of the things a Macbook does, and I would argue that many people would be sufficiently served with an iPad and a keyboard, rather than a Macbook.

Pretty much the only other app that you can use with an iPhone but not with an iPad (and neither a Macbook), for technical reasons, is Wallet.

I think that Apple does not offer either of those apps in iPads because they are not believed to be practical, given the form factor.