I used to think this way too. Until I realized the big difference in viewing my videos shot in 4K vs 1080p even when watching on my 8 Plus. The difference was quite a bit despite not viewing on a 4K screen.
10 years from now, when you whip out those old 1080 vids on your 8K TV, you'll wonder why you didn't have the foresight to shoot in the highest resolution possible.