Plenty of engineers on the market can work professionally in C. Only a small amount of people can write Cobol (or is willing to given that is almost useless). That alone is a good reason to consider Cobol a legacy language and throw away a codebase written in Cobol.
Using DynamoDB in 2025 is such a weird proposition. Horrible dev experience, no decent clients/libs, complex pricing, weird scaling in/out mechanism, slow, it only works well for well defined use-cases.
Running workers ourselves was the last resort, we tried everything else but it was impossible to get fast (and consistent) build times otherwise.
In a way we are now going to get charged for Github's poor execution on Actions.