Older macs were more robust. I think this is one reason of the failure of apple against microsoft: when you have a computer that enables you to do your stuff without problems or failures, you do not need to replace it by a new one. Microsoft has understood how to earn a lot more money by selling half broken products that people want to replace by better ones. Maybe, this was not intentional.

btw, this post is risky for my karma, but I am always suprised to see very old mac still frequently used.