To be fair, usage has likely dropped commensurate with staffing!
>These government systems by necessity are not very complex
I don't believe this is correct. CMS has a bunch of their source code on their website. The COBOL parts are quite expansive and there is probably a whole lot more out there: https://www.cms.gov/PricerSourceCodeSoftware
Look, I have no issue with wanting to modernize government systems. An organization I used to idolize, the US Digital Service, did this as their full time gig... and most of them were just axed. I'm not sure a few 19 year olds are going to do better than this organization. It's hard work.