These machines are revenue generators, utilising fully patented consumable part designs allowing the manufacturer to have the monopoly on spares supply and allowing them to name their price; usually up to 5 times that of non patent parts, leaving you the customer without freedom of choice.
Second hand heavy generation machines and also modern compact machines (modified to run on non patent parts) are available from Doug Booth & Sons, factory re-built to all intent and purpose mechanically good as new available with modern factory inspectorate guarding and auto process electrical control gear.