Who's said they are releasing a cheap iMac????
I haven't read anything about it. Why would they when the sell well anyway?
There was an article on this site about it last week.
It's possible that they are considering it to gain more market share (like they did with the iPhone 5c) but then again, considering how badly the 5c sold compared to Apple's expectations, perhaps it will be put on hold (if they were even considering it).
I personally still consider Apple's computer division as large as it is, a niche... it's really not for everyone. Yes, I do find it easier to use than windows but most people see the cost as a big issue.
I believe that those who buy Macs understand that quality comes at a cost and are happy to buy a Mac that will last 4-5 years with little maintenance rather than a Windows machine that is bogged down and slow after a year.
In more recent years, the iPhone has led to a bunch of new generation mac users who literally buy it because they used the phone and want a mac to match. My brother in law is one of these. He has a 21 inch 2010 iMac which he bought when released and has used it probably less than 30 times and asks the most simple questions that a 20 sec google search would resolve.
It is silly for Apple to target the mass market of people who 'like pretty things'. These are the people who overload the genius bar/one to one help with questions like "how do I read my email..." rather than "since 10.8.5 my time machine has gone super slow... i've wiped it and it still won't work properly".
It is more expensive to constantly pander to the needs of people who quite frankly only need to learn how to do one thing... how to perform a google search (which is probably why the paid for one to one service has came about).