Walt has been pretty low on inventory for quite some time. He's been getting out of selling Jabos for a couple years now, due to his health not allowing him to physically handle it, and has only stayed in this long to sell off the little remaining marbles he has purchased from investors, and a few classics that he earned for helping Dave with the run(s), when not enough staff was on hand. Gone, are the latter. The contract runs were the the big blow, as so many people are now competing for sales. It's tough to really make any money when you pay $300, to $500 for a case of marbles, and are lucky to find one, or two hundred of real quality that can be sold to a collector. With the prices running around $1 each at point of purchase, and dealer, to dealer, one can easily deduce the low margin of profit.
The large amount of people selling marbles got them from the same places as everyone else. You'll find most of them were either invested in runs, or bought from investors, usually predetermined. Some are further down the line, buying as the third, or fourth person. The few dozen buyers of classics from the '90's, on through 2008, and beyond, still have marbles that they have been distributing all this time. Every once in a while, an avid collector will unleash a nice collection for one reason, or another. You can find big jars, and cans of Jabo marbles at nearly every flea market withing a few hundred miles of the plant. They're everywhere. The trick is, finding the rare, and undamaged ones.