I don’t think we’ll see it for a few years, but I feel like Apple has laid out their plans for this when they announced the VisionPro. It runs iPhone and iPad apps in Stage Manager. So does the iPad Pro. And I can definitely see that it’s a possibility for the phones in the future.
Now the chips in the phones aren’t M-series, so it might be a while until we’ve got the horsepower, and I’m sure there’s some developer-changes necessary as well, but it doesn’t seem out of the question.