1) Product managers have more influence and decision making in prioritizing what should be delivered. I have routinely encountered wherever I worked that any work related to improving efficiency or spending time in non-business related work is constantly de-prioritized. Controlling programmers time means certain system bugs get lower priority and junk accumulates over time and software gets bloated. There are code-path ways which are not being used anymore but no-one bothered to clean up as they have not been instructed to do so yet.
2) I find the explosion of javascript in popularity is a major reason of this inefficiency. Imagine the compute and electricity wasted globally because certain developers don't want to build multi-threaded applications and prefer dynamic typing.