Everything matters, but not everything matters equally. If runners didn't think weekly milage mattered at all, they wouldn't talk about it as much as they do, and those counting in kilometers get higher numbers without trying harder, hence comparatively a "free" subconscious boost to self confidence.
If you talk about it then it matters. If you think about it then it matters. If you log it then it matters. Change your talking, thinking and/or logging and you'll nudge the way it matters.
I'll add that the 3:00 vs 5:00 has to some extent the opposite effect when it comes to the 10000 on the track. Running 1000 meter repeats at 2:55-3:00 sets Europeans up for times in the 29:30-30:00 range. Running mile repeats at 4:25-4:30 sets Americans up to run in the 27:30-28:00 range.
There's more to it than that of course - especially since many of the best Kenyans and Ethiopians totally grew up dirt poor without any type of clock or GPS device or track markings available to them whatsoever until late in their teens. But ain't it funny how the numbers play out for those who do use them?