Mardelin--
The type 'fad' you are describing reminds me of a few years back when Disney released
102 Dalmations. It was a HUGE hit with the kids and guess what everyone got for Christmas....yep, Dalmations! And guess where they ended up?

Likewise when Disney released
Finding Nemo there was a run on the pet stores for clown fish. I remember stores here couldn't keep them stocked.
(I'm thinking maybe it was Disney's fault...just kidding.)
Similar situation I am afraid. Sadly, aside from the crossbreeding, I am afraid this is what will end up happening to Yorkies when they drop from #2.

A few years ago, I never heard of a Maltipoo or a Morkie or any of these other lovely terms being used.