Of course when an OS loses support, government and companies should move away from it. That's only logical. Why don't they? I can't answer that. You'll have to ask them.
Your argument was that government and companies are more lucrative and better targets. Maybe... But if they are so lucrative, why don't they upgrade to newer, supported OSes?
So you are saying that Apple users have more money so they should be the targets instead of the government or some business?
Why don't they upgrade? Good question. Perhaps you should ask the NHS rather than me. We are currently running Win10 with no problems with a few systems on 7 until software updates come from our vendors. That being said, they will all be done by the end of this year. We were mandated to get off XP over five years ago due to security concerns and lack of support.