i ask the same question to you. what is so hard to grasp about this?
the difference here is your car doesnt stop getting serviced when the new model car comes out. if apple made cars and you drove a 2011 and took it into get serviced for a problem, they'd tell you you're out of luck, but guess what? the new 2014 model fixes that problem.
"forced" means that an artificial limitation is placed on the software or hardware to coax you to buy the new. its a well-documented phenomenon. You can read more about it here:
http://en.wikipedia.org/wiki/Planned_obsolescence
"a policy of planning or designing a product with a limited useful life, so it will become obsolete, that is, unfashionable or no longer functional after a certain period of time"