Software has become more increasingly complicated over time. Aside from adding new features, many companies have improved their efforts of providing accessible applications to a international audiences.

Let's not forget we've drastically increased security by writing applications in safer languages.

Oh, and newer applications tend to support a far wider variety of devices types, displays, inputs, etc.

Developers definitely be investing a lot more effort into improving the status-quo, but it's unfair to claim stuff is slower without improvements.