That's not entirely true.
Any race with, say, a +2 STR will still able to start with a 20 in STR after rolling a 18, which is not an option for a race with no bonus on that stat (sorry, ABILITY).
That is exactly the reason i said "less" relevant ... instead "irellevant".

Also, maybe im wrong here but i cant help the feeling that if we start concidering all 6 stats, its not so obvious to say wich Barbarian is better. :-/
I mean 20 Str is fine ...
But 20 Dex, or 20 Con is also not bad ... even 20 Wis or 20 Cha can be usefull, for some really wild builds or different uses than attack.
And the beauty of rolling is that nobody say you still cant get second 18 for Str.

It would require a little more re-rolling tho.

I think there should also be minuses to stats for picks. And maximums. For instance, I don't think the strongest halfling should ever be as strong as the strongest half-orc.
Agreed ... but im affraid, that will never happen.