Divide & Conquer divides, but doesn't conquer

[Andrei Alexandrescu]

Another one:

template Filter(alias pred, TList...)
{
     static if (TList.length == 0)
     {
         alias Filter = AliasSeq!();
     }
     else static if (TList.length == 1)
     {
         static if (pred!(TList[0]))
             alias Filter = AliasSeq!(TList[0]);
         else
             alias Filter = AliasSeq!();
     }
     else
     {
         alias Filter =
             AliasSeq!(
                 Filter!(pred, TList[ 0  .. $/2]),
                 Filter!(pred, TList[$/2 ..  $ ]));
     }
}

Why cut the problem size in half if it doesn't improve complexity?