The problem is that everyone here is looking at it from a software design standpoint, not a software development standpoint. Once you look from the latter it's obvious why things are the way they are: businesses are trying to cheapen out on software development costs. As a result, software quality cheapens.

For example, if disk space is abundant and very cheap, and optimizing software to use as little as disk space as possible is relatively more expensive than throwing more disk space at the problem, you shouldn't be surprised that software starts using more disk space than necessary, because what's being optimized is software development costs.