Have you ever sent a customer care message to AA? AC?
They're all the same.
Post travel resolution is rarely time sensitive, it's not exactly an area that businesses want to allocate resources to when there's no calculable ROI.
If you were running AS and had some funds to allocate, would you increase the budget to a cost centre like post travel support, or would you invest it in something that will improve guest experience like new lounges, Starlink installations, etc?

There's also a chance that sending follow up emails/responses puts your ticket to the back of the queue again. I've seen that happen before with Zendesk and other support platforms.
As you can imagine, there's no one looking at the inquiry until it's assigned to an agent when it reaches the front of the queue. Sending follow up emails won't change that.