I am talking about machines with less than 2GB of RAM, running modern versions of Firefox, Thunderbird and OpenOffice in addition to all the custom software required for the jobs (including, for some, the Java SAP client). You get why people complain about the computers being slow? FF is notorious for memory hogging, Thunderbird is not much behind it, and OpenOffice and SAP GUI are Java crap which means a tendency to leak memory the longer you have it running and general downsides of simply being Java. The machines swapped like hell, and SATA disks were not a given.
In addition, web sites themselves have grown in resource usage in an exponential way. HN and Fefes Blog are the only two websites I know that I can use even when my data allowance on my phone is finished and I'm throttled to 56k. Everything other? Forget it. And it's not just data usage, it's also RAM and CPU usage, e.g. due to ads and dozens of trackers.
> network config
Actually, it's not the config that's the bottleneck - it's the uplinks and crosslinks between the dozens of city buildings which includes the schools - mine, for example, was linked to the central DC with a 10/10 fiber 14 years ago and still was when I left the school 6 years ago, you can guess how much "fun" that is to use...