Curious how many posting here have actually been part of the process to bring an injection molded part into production. It's a complicated, costly, and lengthy process to get tooling designed, manufactured, and set-up for actual use on a product line. It's not something you simply choose to switch manufacturers on a whim - switching manufacturers often includes having new tooling made to accommodate the specific machines utilized by that different manufacturer.
In a previous life, I was beholden to a specific supplier for my plastic parts ordered in the hundreds at a time. If that company was backed up with orders for other industries that buy parts by the 100s of thousands, too bad - I simply had to wait (sometimes months) until they ran my small batch. When ordering even 1000 pieces of a given part, the largest expense was tooling set-up time and not the actual parts themselves. And when tools aren't in use for producing parts, there's a cost for stowage in the warehouse until it's time for a new batch of parts to be made.
I would have loved to bring this part making in-house, but the cost for machinery was beyond prohibitive and I didn't have the cash to also invest in tooling and skilled labor to set-up and operate the machines. O, I should also note that environmental laws are a major factor, in conjunction with labor rates, for these parts being made overseas on not here in the US
Not offering excuses for Stern, just bringing some industry insight into the discussion to aid in understanding that not everything is as simplae as it may appear on the outside looking in