Same as if you're using that 1970s car to transport that kidney or as a electric generator for your nuclear power station - you sign a support contract w/ the manufacturer to cover that, or you're out in the cold.
But realistically speaking, you could just keep using XP. If you're not surfing the 'net on IE w/ it, then most of those security updates don't even do anything for you.
Personally, I think Microsoft should let anyone who wants to buy extended support do so. They're trying to get ppl to go to a subscription model for software (Office 360), and here they have a bunch of ppl that don't even need convincing - they are asking for it with open arms. It's not like they make money on computer hardware sales, so this seems much better for them. It's okay, I think, to just make tons of money, rather than try to be like the cool kids.
BUT if they don't want to, they totally have the right not to. A lot of those posts sound like they're written by communists, not freedom lovers. We tell people to chose free software - that's freedom. To force people to use free software, to force businesses to open source - that is not freedom. That's forcing your ideology onto others, like the communists found they had to do because people weren't being selfless by themselves. Freedom is letting this thing go end of life if that's what MS wants and letting the people chose again - this time, hopefully, they will chose better.