Its still relevant because, ideally, you are still playing a member of that race and thus are affected by the attributes of said race no matter how relevant or irrelevant they are to your class.In any case, it is the individual character concept that determines where the ability score improvements belong. A statistical average is irrelevant because outliers are outliers.
And yet D&D basically invented the dexterous elf.Personally, I resent "agile elves". According to my reallife culture, elves are personifications of fate and magic, and sunlight. Arrows and Dexterity are irrelevant, and belong to the folkbelief of someone elses culture. I dont want someone elses fantasy racism to interfere with my cultural understanding of what an elf is.
If the default ability score improvements are +2 to Intelligence, Charisma, or Wisdom, and +1 to any other, I wouldnt complain. Essentially the elf is a "mental race" that specializes in magic. But this predeterminism would also be wrong, because D&D also has traditions of elves with high Strength and high Dexterity, and there is no reason for any fantasy racism to interfere with these elf concepts either.
Relatedly, D&D has many different kinds of elf. There are 3e Intelligence sun elves, and 4e Intelligence-Charisma eladrin elves. These elves lack Dexterity and are closer to personifications of magic.
Allowing every race to include individual character concepts is a win for the D&D game as a whole.
And no its not a win for D&D but a huge loss. You lose history, you lose the flavor of different races and you lose the role in role playing because this change signals that WotC is now considering roll playing the default, playing optimized combat stats. Because there is no other reason (except for a minority who think fantasy elves being different from humans is racism) to have floating ability scores except to minmax your combat power and many people on this board have in the end advocated for floating ASI because "it will allow them play different race/class combinations" as for them playing something not optimized is unthinkable (because they would suck and not be competent. Their words...)
Sadly WotC seems to (probably rightly) think there is more money in tactical boardgames instead of RPGs and thats the direction where they are going. Not playing the "elven blacksmith who picked up a blade himself" as a role, but the "+5 attack AC 16 damage dealer" role.