Software complexity is increasing. With the increased complexity many failure modes are not understood by developers. Thus those failures are not handled gracefully. This feels like a decline in quality. Depending on what you measure the quality could actually be better, the same or worse.
This inscrutability of modern software is one of my biggest pet peeves with it. There was a time when the resource-limitations of computers forced software to be much simpler - and the end result was that when things went wrong, someone with sufficient time and motivation could sift through the rubble, figure out what the problem is, and often lash up some kind of workaround. That's getting harder and harder to do these days.
Likewise, in the open-source world, the breadth of dependencies is getting out of hand - I've lost count of the number of times I've tried to build something and had to go on half a dozen side-quests to track down a particular version of a particular build tool because the version in my distro is either too new or too old.