Costco used to buy kosher beef, but now has their own wiener factory just for making these hotdogs.
In a Seattle Times interview in 2009, Jim Sinegal (founder of Costco) was asked about the $1.50 price for the hotdog. "What would it take to raise the price of the hotdog?" "That would mean I'm dead."
Craig Jelinek, Sinegal's replacement, said in a 2018 interview he lamented to Sinegal that they can't keep doing the $1.50 hot dogs -- which should cost $4.40 nowadays with inflation. Sinegal said to him "if you raise the fucking hot dog, I will kill you; figure it out."