Re: Schools need to step up to the plate
"As I think everyone here will know, you really don't need lots of expensive kit to teach IT: business cast offs work fine."
In principle, yes, but managing a group of disparate, older PCs adds in lots of extra support time and costs too, something few schools have. It might work in a minority of schools where they have someone with the skills and interest to support the old kit and source the parts when the older kits breaks down, but if/when that person moves on, they have a problem again.
Then you also hit (sometime unfounded) worries over regulations etc regarding disposing/selling of electrical equipment. Someone has to test it for electrical safety and be responsible for the certification if anything goes wrong. Lots of businesses really don't want that hassle so when refreshing their PC fleet include disposal of the old kit as part of the deal. Those taking the old kit may refurbish and sell on or just subcontract the collection down the line. Then the school has concerns/worries of buying in and insuring second-hand kit that might not even last a year.
Most of the schools I deal with very much prefer to buy new with a 5 years on-site hardware warranty. That's desktops, BTW. They few schools I've dealt with going for minimal levels of desktops and have handed out chromebooks or Tablets seem to have ongoing "user damage" repair costs which far outstrips the cost of having lots of desktops. Likewise, a very small number have mobile trolleys full of laptops they move from room to room as required and also end up with lots of user damage.
Regulations that are real, regulation that people misunderstand, the ubiquitous "health and safety" mantra and which budget gets spent (capital versus running costs) are what make it difficult to use recycled/second-hand PCs in schools