it was using 4 trumpets at the unison, not 6, it's the orchestration that make it stand out, he was doubling some harmonies in a very intelligent way with strings and synths.
Again, it's a matter of orchestration and mixing...
it's not only a matter of orchestration but a matter of power : 3 trumpets playing triple forte will have more power than 6 trumpets double forte ^^
the real problem is that John William's music need triple forte sample