If 5.9" were ridiculously large (it is), then so is anything bigger, including the phone that must contain the 5.9" screen.
A 'smaller' screen can actually be larger in area. Take the 5.7 inch note 3 mentioned earlier.
https://m.gsmarena.com/compare.php3?idPhone1=5665&idPhone2=1...
Its screen is nearly 7% larger than the 5.9 inch zenphone 9. Skinnier aspect ratios exaggerate the growth in phone screen sizes.
http://www.displaywars.com/5,9-inch-d%7B20x9%7D-vs-5,7-inch-...
If 5.9" were ridiculously large (it is), then so is anything bigger, including the phone that must contain the 5.9" screen.