I've not seen a 50 series Waterloo tractor in the wild for 15 years or more. The last one I know of was pushed into a container and shipped off to work on a sugarcane plantation with a knackered engine and transmission. The 10 series Mannheim and Waterloo tractors are looking pretty tired now too now.
You say I don't know about the financials. I know enough that we can't afford to run old tractors anymore. Most farms here are clearing out anything that can't earn its keep and replacing multiple units with one big machine. That one machine has to run, so is often leased and rolled over every 3 years or so. The labour costs are too high here to make major surgery on machines worth while, so generally they will get shipped out from paces like this
Cheffins - Farm Machinery & Plant Auctions for export to countries where labour is cheap and it is more economical to make big repairs.