Yes, it is common for data center workers and tech support to move up to sysadmin or something similar sometimes even SRE.
They are given a 6 month trial period on a team to train and then go through the external interview process afterwards
> That's something they should bring to Modis, their employers
The whole point here is that they effectively work for Google, and Modis is a layer of indirection that enables Google to exploit them, so bringing this up to Modis is kind of besides the point