It's not really related that directly. We have no idea how Disney was managing their supply chain and quantities.
While it could be there's containers full of Disney merchandise waiting to unload sitting just off the coast. It could just as easily be that there's nothing for Disney in the pipeline at all, that they delayed purchases and slowed down the entire supply chain during the pandemic. Then, ran into issues ramping it back up all the way at the manufacturing end now. Especially if those manufacturers switched to other clients during a lull in Disney orders. It's not like we've ever seen Disney slow something down during a downturn (only every time).
Disney is actually big enough that they could bypass the entire port bottleneck and fly in cargo directly. It would cost more, but if anyone has the profit margin to absorb the difference, it's going to be Disney.
Just like the chip shortage for can manufacturers has nothing to do with the port backup. There's not automotive chips sitting off shore not getting to the factories. They delayed orders when sales were down, then went to ramp up later only to find out that electronics makers used up all the capacity. Now the auto companies are at the back of the line to even have the chips made.
Lack of product in a Disney store and the ability to buy TP at the grocery store aren't that related.