Exactly, there's almost no benefit to them to push the state of the art as they're not an end user product at present (whether or not that should be the case is

Exactly, there's almost no benefit to them to push the state of the art as they're not an end user product at present (whether or not that should be the case is up for debate, but since most people don't care). Apple is nudging consumer behaviour with each product transition - I wouldn't be entirely surprised if we start seeing more devices with mobile data built in (say, with an antenna behind the logo or behind the Touch Bar).