Apple built their own search engine over 5 years ago, under the Siri / Spotlight umbrella. When people talk about Apple building their own search engine, they generally seem to expect a website dedicated primarily to web page results, but under the covers what powers Apple's Spotlight results is basically a search engine.
The big question would be what Apple would gain from a dedicated website for search results. Would people really switch to it from Google? Why would it be a better delivery mechanism for search results than Spotlight? Not sure the answers to these questions has changed much, from 5 years ago to today.
They have a lock on mobile devices for the western world. They can by default pry away search revenue from Google at a large scale. They have the cash reserves to see this done properly. They'd be crazy not to come onto Google turf. Their hardware lines are sagging revenue growth wise. Service revenue is their biggest growth area. I have no idea why they didn't do this before.
> They have a lock on mobile devices for the western world.
They don't though. There are only a couple countries where they're more popular than Android, and only barely there. There's no country where they have 60% market share.
Or just like Iran's nuclear program, they can extract more concessions if they are permanently 1-2 years away from deploying a search engine. Google's spot as the default search in Safari already earns Apple billions per year.
It might look like that for people inside the walled garden but I suggest applying for an exit visa to have a look around the great wide world out there where you'll quickly find out that it is a whole lot more diverse than the picture painted inside the walls. Not only is it more diverse, those rumours spread about the constant onslaught of viruses on those poor creatures on the other side of that big, safe wall turn out to be untrue, most people seem to never have even seen one. Even stranger things will start to become clear, like those supposedly poor and oppressed outsiders needing far less money to get around the world than those inside the walls while at the same time having are larger choice of methods to navigate it. It wouldn't surprise me if you decided to stay, just don't forget to plan this carefully so your identity does not get stuck on the inside after which you won't be able to message your friends any more. It is a bit tricky but it is doable, many others have gone that way before.
If Apple Maps has taught us anything, probably not. But Apple would first need to pour an equally large amount of resources into web search, they way it did for Maps.
