This article is very sparse on details. For one, the factory that makes the Costco balls primarily makes Taylor Made balls. The manufacturer is a Korean company that used its excess capacity to make Costco's balls. Taylor Made sells premium balls so they're pressuring the manufacturer to not do this in the future.
Also i haven't seen any details about Costco having a golf ball design team. Where did this design come from? Did they contract it out to one of the small manufacturers that he article refers to? That's mainly the thing I want to know, since if it's truly their design that they own, then they'll be able to find someone to make it for them.
Also Aschunet isn't that deep pocketed. Their annual revenues are $1.5B with ~$70M shares outstanding and an EPS of about 6, so about $400M in profit, and operating income is in the range of $150M. https://forum.mygolfspy.com/topic/14841-acushnet-losing-sale...
Unlike the small ball companies they sued, Costco is a much bigger company than Acushnet and can afford to fight them off, especially since Costco has the distribution scale, hype, and demographic fit perfectly suited to really move the needle with this product (The upper middle class family with disposable income that is budget conscious, which is Costco's main market, is perfect for a budget high performance golf ball, which is a perishable sporting good that you need to buy hundreds of if you play regularly).
(Fwiw it is very common in the sport to have small upstart club makers. Basically all you need is a milling machine to make a perfectly reasonable iron or putter, and every now and then you'll see a random small manufacturers club in a tour player's bag - ex: the Yes! Golf putter when Retief Goosen won both his US Opens)