iPad Resolution Question

I’m a unsure how screen resolution really works so would appreciate any comments to help clarify.

I have an original iPad with 1024 x 768 resolution. I use the iPad only occasionally and now want to buy an iPad Pro 9.7 with 2048 x 1536 resolution so I can watch HD TV & movie content in higher quality when away from home.

Using Blu-rays I can create heaps of TV show episodes with 1200 x 900 resolution. These episodes look OK on my original iPad considering the iPad must be scaling the resolution down to 1024 x 768. You would think with an iPad Pro now being able to display the full 1200 x 900 resolution there would be a big improvement in quality.

However, I have read an online article which states there is barely any noticeable difference watching HD content on a 1024 x 768 screen compared to a 2048 x 1536 screen. A 1024 x 768 screen can only display a maximum of 786,432 pixels. A 1200 x 900 TV show playing on an iPad Pro is displaying 1,080,000 pixels.

Considering this is a pixel increase of 37% being displayed on the same size 9.7" screen, how can this not translate into a clearly superior quality image on the iPad Pro? How am I misunderstanding this difference in resolution vs picture quality?