It all comes down to text input. Steve Jobs launched the iPhone with only a touch screen but he launched the iPad with a hardware keyboard accessory (discontinued after a year but then reintroduced with the iPad Pro). So with iPadOS it’s always really been touch+keyboard and frankly mouse+keyboard is better.

If Apple managed to offer a revolutionary input for the iPad (perhaps subvocalised speech input or a a redesigned touch/pen input) it would be the first step to a touch-centric interface as capable as keyboard+mouse