eInk devices are very much not converging to 16:9 or wider aspect ratios. This device is intentionally the size and shape of a reporter's notebook, but there are virtually no other eInk tablets which diverge significantly from more common paper aspect ratios – they all (ReMarkable, Supernote, Boox, Kindle, etc.) are and continue to be exactly what you say you want.

I believe most of those are 4:3, but point taken.