“There’s an old restaurant saying: if you want to sell it, crumb it” was cited in print in 2009. The saying means that restaurant customers love food coated with breadcrumbs, such as schnitzel (German), tonkatsu (Japanese crumbed cutlet), pollo milanese (Italian chicken breast with breadcrumbs), and many other international dishes. The author of the saying is unknown.
 
         
Waitrose.com
Google Books
Waitrose Food Illustrated
2009
Pg. 28:
There’s an old restaurant saying: if you want to sell it, crumb it. That sums up the schnitzel’s popularity.
 
Japan Tourist
Dontsuki Izakaya right in the heart of Teramachi
Bonson Lam
13 December 2011
(...)
The crumbed pork cutlet was also beautifully fried, and went well with the pickles, miso soup and rice.  The barman tells me, ‘If you want to sell it, crumb it’. He is of course referring to the addiction we seem to have with hot food, crispy on the outside, tender on the inside.
 
The word panko comes from the Portuguese word for bread, and the Japanese word for crumb.  A perfect marriage of west and east.  It is made from Japanese wheat bread, which is slowly dried and then shredded into crispy flakes. Because they are crispy to start with, they are super crisp by the time they come out of the fryer.
 
The Telegraph (UK)
Bring out the breadcrumbs
Whether you whizz up your own or use a shop-bought packet, breadcrumbs can transform a chicken breast or slice of aubergine into a homely treat.
By Bee Wilson
7:00AM GMT 12 Feb 2012
Apparently, there’s a saying in the restaurant world: ‘If you want to sell it, crumb it!’ There’s something about fried food in a golden crust that is very hard to resist. No matter how grown up you believe yourself to be, breadcrumbs speak to your inner six-year-old, who only wants to eat fish fingers.
 
Almost every food culture seems to have its own version of the schnitzel. The Japanese have tonkatsu, a crumbed cutlet, most often pork, served with a thick curry sauce. Americans have breaded veal chops (and plenty of other breaded things besides). And the Italians have pollo milanese, flattened chicken breast coated in egg and breadcrumbs, sometimes with a little parmesan.
   
Gourmet Traveller (2012?)
Neil Perry: Crumbed pork cutlet with sautéed apples, potatoes and sage
“A great friend of mine says, ‘If you want to sell it, crumb it’. He is of course referring to the obsession we all seem to have with crisp food. I have never met anyone who didn’t like schnitzel, and this crumbed cutlet is a form of schnitzel. Here, as always, I’m suggesting you take the high road and make your own breadcrumbs, but if you don’t want to, just use the bought variety and the result will still be very satisfying. If you can get your hands on some beautiful small kipflers, leave them whole in this recipe. If, instead, you are using pink eyes or similar, you may want to cut them in half.” - Neil Perry
   
justb.
Golden delicious – a fennel and thyme gratin
Written by Sophie Hansen
September 12, 2012
(...)
A good crumble top gives any dish colour, extra taste and a consistency that appeals to everyone. Neal Perry says in his epic book Food I Love, “if you want to sell it, crumb it”. I couldn’t agree more!
 
The Times of India
Garnish your dish with breadcrumbs
Saadia S Dhailey, TNN May 7, 2013, 12.00AM IST
Golden and crispy on the outside, it looks so tempting that it doesn’t really matter what’s inside—this is what breadcrumbs can do to any dish. In fact, there’s a saying in the restaurant world, “if you want to sell it, crumb it!”

Every culture has their own recipe with breadcrumb coatings. And they cover meats, seafood, as well as vegetables, and even fungus (we mean mushrooms).