Dawg what are you talking about?! Marketing is Nike's bloodline and what they do WELL! Are you not familiar with Mars Blackmon? Are you not familiar with The Lebrons? Are you not familiar with the Kobe x Kanye commercial? Did you not see all the Space Jam marketing that took place in LA and NY and around the world? Did you not see Lebrons come out of nowhere commercial? Did you not see Kobe's conductor commerical? And that's just a snippet past and present of the athletes you named. Have you heard of Wieden+Kennedy? Do you have Twitter or Instagram? Do you see how much product the seed to folks they deem influencers? Nike IS Marketing and they spend BILLIONS on it...just because they're not showing commercials during every break of every game doesn't mean they aren't marketing. Nike is about seizing the moment and those moments are seen by millions i.e. SuperBowl, ASW, etc. So, YES Nike does market and allocate funds to athletes but you are CORRECT by realizing they are putting those funds to athletes like Kyrie and PG because they have way more playing years than Lebron.
Lastly, Nike did NOT sign Lebron to a lifetime deal because of marketing money, they signed him to a lifetime deal because he is currently the greatest player in the world and that is way more valuable to them than *insert name of an upcoming athlete*.