The thinking goes something like this:
Dealer or Distributor: Hey, I'd carry your products, but if I hafta match prices, I can't make any money.
Manufacturer: What if we can create a special model that other dealers can't get? That way, nobody can ask you to price match. Of course you'd hafta buy a lot of mics, but they'd be special to you.
Or the Dealer or Distributor might say: What if you make a special model that other dealers or distributors can't get? That way, nobody can ask us to price match. Of course we'd buy a lot of mics, but they'd be special to us.
The mattress industry works the same way. "We'll beat any price on the same model", but they know that all the mattresses they carry have a special model number that only they use.
Grocery stores use the same technique with their house brands.