And that might be realistic, but it's not fun.
If I'm facing a level 1 foe at level 1, I have many ways of dealing with them. I can try to outrun them (Athletics). I can try to turn them to my side (Diplomacy). I can try to coerce them (Intimidate). I can try to fool them (Deception). I can try to understand them (whatever knowledge skill is appropriate).
But at level 8, or even higher, facing an 8th level foe, some of those avenues will be harder than they were at level 1 against the level 1 foe. My competence, relative to the challenges I'm facing, have narrowed.
It doesn't matter that I'm much better at dealing with, say, a level 4 foe at 8th level even in my weaker areas, because the chances of a 4th level thing being a narratively meaningful challenge are nil.