Please explain: Why does .01 second mean so much for football players?

Yeah, just like most sports fans, I pay attention to stories about the NFL Draft, though there are almost none of them I actually take seriously. They're good reading, but to tell you the truth, the stories are nothing but late winter/early spring content fillers.
Think about it.
Why does ESPN make a big deal over Mel Kiper Jr.'s Mock Draft 1.0 or 3.0 or whatever version it is? Why does CBS Sports produce a new mock draft story every week?
The content isn't very different. There are mild changes from week-to-week, but nothing major. Yet there is a subset of fans who hang on every word, every week and the version 2.87 or whatever it is on a given week.
Yeah, the information may change slightly. But how much?
I guess it depends on Pro Days, or at least it comes across that way. Breathless reporting of 40-yard dash times seem to be the "make or break" for some players whether they've got game...or not.
Really, some day, I want someone to explain to me the difference in speed between a guy who runs a 4.35 and a 4.40 40-yard dash. In their gym shorts. And t-shirt. In track shoes. Straight ahead with nobody chasing them or tacklers to try avoiding.
What does it mean? Seriously! I want to know. Given the two times above, is that going to tell me if one guy or another is going to be an NFL star? I'm no scout or expert or "Insider" or anything like that, but the whole things just makes no sense.
Think about it.
If I'm chasing you and there's a fraction of a second difference between my speed and yours there MAY be a scenario where you'd run away from me. But not in the course of 100-yards. It equates to what--roughly 0.15 seconds over the length of a football field?
It seems like pro football scouts would want to see game speed. Wouldn't you? If the guy I'm scouting is running people down on defense or running away from people on offense, who cares if he runs a 4.5 second 40-yard dash. Does it matter?
Honestly, I don't understand and have never understood the absolute fixation with physical testing in the NFL. Fans--and apparently scouts/teams are fixated on skill speed sets and seem to sometimes to forget whether or not someone can play.
It happens over and over and over again.
Yeah, sure I get it. This year, scouts aren't as high on say Mac Jones of Alabama over Justin Fields or Trey Lance because Jones isn't very fast and an old school traditional drop-back passer at Quarterback.
Does it mean Jones will not be as good a pro as either one of them?
At this time, who knows?? It depends a lot on the fit.
In fact I'd argue that a LARGE percentage of kids looking to go from College to Pro Football will be successful IF they land in the right situation to fit what they do well.
In MY opinion--for what its worth--if you put 100 players in 100 places, the ones in a system that fits what they do well will be successful, the others won't. The NFL more so than any other sport tends to try making players fit the system rather than fitting the system to the players which is why you don't have much change in successful or unsuccessful programs.
It applies to College Football too, but is even more pronounced in the NFL.
It doesn't matter if Fields or Lance have more physical skill than Jones if Jones lands with a team that runs a system which fits his skills as a drop-back QB. Putting him (Jones) on a team that runs a ton of RPO and expects the QB to run the ball a lot...no, that is probably not going to work.
The same for the mobile guys. Put a Fields, Lance or Zack Wilson in an old-school, traditional drop-back offensive system with few options to improvise or run, no, they're probably not going to do so well.
I've always read, or seen that a coach who adjusts what they do to the people they have doing it always seems to stand out and be successful. Sure, there was a time and a place where if you went to "Team A" you were going to run their offense the way they've done it for decades. If you went to "Team B" where the coach/system was flexible and adjusted....you had a chance of becoming a star.
Hey, I could be reading the tea leaves all wrong. Maybe fractions of seconds do matter in all situations. Maybe a great strength and flexibility test is what is the key to success in football, I honestly don't know. I'm not a coach and I'm not a scout.
But I have played sports at a medium level. I have seen and observed how things seem to work and on the surface, I'm feeling like I'm on to something here. Do a little reading on Nick Saban and Bill Behlichick and how they tailor their system to athletes. How they teach players to be disciplined and focus on what their job requires.
It might give you some insight on their success and why they don't subscribe to the best test scores win.
But I could be wrong or could be convinced otherwise. What about you?