I do think it is a reasonable decision. Supported older outdated software costs money, and Apple have to pass this cost onto newer customers in the form of higher prices. Apple have also priced updates to later versions of the OS to be very affordable. I don't think it is fair for people running old equipment to expect others to pay to keep their equipment running.
Eventually in every software's life cycle the company behind it stops providing updates, the company has moved on to their other products and no longer wishes to dedicate resources to the product, so I do agree with Apples decision to no longer provide security updates for Snow Leopard it was announced well ahead of time of when they would stop updating and everyone knew the day would come.
Apple has made the right decision to stop providing security updates for snow leopard because this will enable them to fully focus on updates that will affect most of the consumers. The executives at Apple know what they are doing and the general public do not need to questions their motives.
No. Windows XP has been supported for over 12 years and just now stopped receiving security updates. Windows XP, although dated and hazardous now, is a very useful operating system, still. Just because it's older and not as useful doesn't mean it should be cut off. I have a Windows XP computer with Service Pack TWO and I still get a lot of use out of it, and it's from 2003. So like I said...Just because an operating system is old doesn't mean it is useless.
I do not agree with Apple's decision to stop providing security updates for Snow Leopard. I feel like this came up too quickly for this platform and they are doing it prematurely. I understand that its difficult to provide these updates after a certain amount of time, but I don't think they're making large strides to provide new and advanced products at this point.
There does have to come a point in the life cycle of any piece of software that the owner, company or provider ceases updating it because they need to focus their resources on newer products. However, Apple users are notoriously loyal to their brand, and Apple might be hurting future business by abandoning current users.