hmm..and you're point? Andorid has specs for the target use, i.e. if you only want to browse the web, watch a film, read or listen to a book, why do you need to spend $600 when you can spend $60 for essentially an identical overall experience. No doubt the iPad is a premium device but for what most people use them for [see above], it's a premium price to go with it. Likewise when the use is more widespread and intense the Ipad [Air & Pro] handle that with a breeze, but then so do Galaxy S tablets.
You just stated the issue right there.
When people want a premium tablet experience, they buy the higher-end iPads, which are already dipping into laptop-pricing category, and this is without the Apple Pencil and smart / magic keyboards. What this also means is that the iPad remains a lucrative product category for Apple, which in turn means that Apple does not hesitate to invest additional resources in developing the iPad platform.
So when someone buys an iPad, they are also buying into the apple ecosystem. This means the A-series processors (souped up if the timing is right), which in turn guarantees 5 years of software updates, a library of optimised tablet apps (eg: lumafusion for video editing), and full integration with other apple hardware and services.
Compared to this, a Samsung tablet is a lot less appealing.
Conversely, based on your assertion, the only time anyone would buy an android tablet is when it's being sold at a price point far below even the cheapest iPad that Apple has to offer. At such low margins, these tablets are unlikely to be making the company much money, which in turn means that said company probably can't afford to invest too much into supporting and developing them further.
Expect this disparity to only continue to grow with time.