Apple has a well-integrated software. It's a benefit to own Apple's full stack of products, but it's not a benefit when it comes to hardware.
Even though the ingredients needed to double as a laptop are present in the iPad, Apple insists that it will remain a tablet. A convertible Mac will probably not exist. Probably.
We know that Apple is working on a hybrid device that would turn an iPhone into a laptop thanks to a patent that was filed in 2017. Correct, you read that on an iPad. The conceptual device is a display with a battery, and when inserted into a slot where the trackpad would be, it transforms into a laptop. The phone provides processing, graphics, memory, and storage.
In another iteration, an iPad slots into a gap where the laptop screen would reside, providing the visuals and power for what is essentially a standard laptop deck and the frame of a display.