Chimpanzee's are genetically 97% human, but they're pretty different.
Seeing as we're so genetically close, it is bizarre to geneticists that they're incapable of swimming or achieving other human simple actions. It's not all one-sided, for weight to force, a Chimpanzee is like 3x? stronger than an average human being; why are we so fragile?
Brawl was 90% melee, if not higher. Smash 4 is 90% brawl, if not higher. Going by some DNA-logic, I'd say Smash 4 is 98% melee while Brawl is 97% melee, it's not even comparing apples to oranges, but rather jazz and royal gala.
The metas of each game impact on each other. I would say prior to Brawl, the Melee meta had no idea what camping/neutral game was; I'm not joking. Look at where Marth was prior to Brawl (tied #1 with Fox) and see where it went from there; cross overs of players and strategies, new and old players alike in Melee started to realise the potency of patience and neutral game, and since then people have stopped freely running into Marth's grab, they don't approach him in the lead or even while they're losing, they have to fear his down air and forward smash set ups only up until a certain percent, and they're play passively until that's no longer a problem before choosing to go hard as the risk/reward is no longer in Marth's favour at all. "Air Camping" and "Ledge Camping (planking)" were unheard of in Melee but became very popular strategies in Brawl with the likes of Wario and Meta Knight respectively, Hungrybox has developed his jiggs much like you'd expect a Wario to play in Brawl (and it contrasts heavily to how Mango played jiggs prior to Brawl); and let's remind ourselves about how M2K planks Captain Falcon's with sheik's up-b with near-impunity.
Strategies that work in one game are likely to work in the other, maybe not as effectively, but they still do. All the games highlight different facets that result in straying metas which realistically still all converge at the tippity top/highest level possible. Within the past year Melee only players/commentators alike are talking about how "soft hit aerials" are the new meta for getting combos/kills, yet in Brawl where there were no such natural combos [into kills], we had to rely on such things to get true combos the entire time, I sit there in contemplation every time certain things are getting hyped in Melee that were staple mid-level barriers in Brawl.