> on the back like it is on most Android phones

The jury is solidly still out on the "better" part. There's no consensus between customers on this topic. Manufacturers who placed the fingerprint sensor (and power button, earlier) on the back, or even the side despite the clear disadvantage of having a tiny sensor, did so to make the bottom bezel slightly smaller, not because of proven better ergonomics. And given the opportunity they switched back to the front, under the screen. Most also chase thinness at the price of smaller batteries which says nothing about the soundness of the decision.

> This home button/fingerprint reader combo is taking up so much precious real estate

The button is there because the design comes from a time when the screens were small so on-screen buttons were a waste, and the body needed to be large enough to accommodate everything else. This phone is an iPhone 8 with a better SoC. It's not a new design or even a redesign.

The design isn't bad, it's old. And it's old so it can be cheap. They achieved a worthwhile result a pricepoint where at the very least it provides exceptional software support and a current generation SoC. There are few phones that serve that segment (OP5 was pretty much the last one in the price range - good SoC, OKish support, regular old bezels). You can freely sacrifice this for better screen to body ratio phones if that quality is more appealing.

I have used android phones with a backside fingerprint scanner and it worked really well. Apple can be incredibly stubborn some time and hold onto something for way too long. It was the same with the one button mouse.

Probably to allow unlocking without lifting it off the surface it's on.

The main button was on the front, so they integrated the fingerprint reader into it. Moving the main button to the side or back might have worked but would have been non-intuitive for many users (e.g. my mom just realized her iPhone 11 that she got launch day has a mute switch, and that she has had it engaged for weeks). A back fingerprint sensor would also require some gestures to change, such as swipe to unlock - attempting a complex motion while also attempting to reposition your grip to hit a sensor on the back is going to increase drop rate.

They got rid of the button and the fingerprint sensor in one go, so there was never an opportunity to have just a fingerprint sensor on the back.

It's frankly one of the reasons I got rid of my iPhone 6S shortly after buying it, for another Android phone. A lot of Apple's ergonomic choices just seemed bizarre to me compared to most Android devices. I'm sure they've gotten better since, but things like the fingerprint reader on the front were in my opinion bizarre and made me have to completely hold the phone different just for my fingerprint, where on most Android phones my finger is already right there in its normal usage position in my hand.

Which is why Apple created Face ID to solve this problem.

This action is fairly annoying to have to do constantly.