Think about it, Usain bolt can run 19.19 and 9.58 for 100m, but he will likely not break the 5 minute mile. Longer slower easier runs will help your 5K but you'll lose some of your 400/800 ability.
Too bad that Bolt stated 3 years ago that he ran 2:07 in a 800m, and could easily break 5 min mile when asked if he could, quote: "Lol, I'm not that bad"
People don't understand that Olympic participants aren't just physically in good shape, but also mentally. Bolt knows how to suffer. He might not have the VO2MAX or lactate threshold of a top miler, but his speed and determination alone and all the miles of running he did will carry him to a sub 5 mile.
Same in tennis - Nadal is a sand specialist, still does well on other courts. Same with Federer and grass.
Same in skiing - the top athletes like slalom specialists Shiffrin and Hirscher can still throw down some very respectable Super-Gs (competely different event) and compete with the best there.
10 years ago I was a trained pure speed sprinter and was pretty fast and age graded 90% at distances between 60m and 200m but not until I started being competitive at longer distances after my sprinting career was over did I truly know how painful it was.
Until Bolt actually goes out there and runs a sub 5 mile, I shall have my doubts - I do not disbelieve that he could do it and it wouldn’t exactly shellshock me if he was way under, I would just like him to prove it. Untrained for distance, pure speed guys die fast and because a lot of pure speed guys are so used to winning races before they start to hurt, they rarely know how to push past pain the same way middle distance runners do.