[a15971]

The bloat is simply a side effect of the evolution. Software is not as much designed as evolved.

You make a name for yourself in SW development by adding features that others deem useful. You get money (in commercial setting) or prestige (in freely distributed software) if you seem to be producing something useful. It's trivially easy to recognize a contribution that adds code, but it's hard to recognize a contribution that means absence of something (e.g. absence of bloat, absence of memory hogging, ...). You get inclusion in newer, larger or more important projects easier the more you make yourself recognized.

So any useful software gains more contributors that add things than those who remove things. Commercial code can and does gain developers if it earns money, open source software gains developers if it is deemed useful by programmers.

This is a force that shapes both the group of involved developers and the resulting software in a process akin to evolution. In both cases the selection is biased towards adders of code. There's also always possible to add improvements that help some use cases and audiences. On the other hand, arguing for removing something or limiting might make you unpopular (you are seen as an obstacle to everlasting progress) and removed from the group of developers. Rare people have enough recognition and clout to prevent inclusion of something (Linus Torvalds is one of them - he can get away with rejecting patches to Linux kernel and he can play the role of the kernel guardian).

On the whole, software expands until it fills the resources available.