What would you prefer? To pay for extended support or pay for a large number of new PCs? There are a vast number of XP machines in all sectors and upgrading them with some specialised application that they run could cost significantly more. Yes, they will be updated, but in a timely fashion.
Several of the companies I deal with still have systems that run Win3.11 and Win NT - the equipment is from one source and support is still provided for those. The total cost to the end users of an upgrade would be measured in hundreds of millions of dollars whereas the support is probably around $1m.
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