Or the simpler explanation is that they have thrown a couple of people in each country and they are totally, totally overwhelmed as it really requires a far better base and thousands of full time staff, because nobody at Apple is going to spend any money sorting this **** out.
Why does it require thousands of full time staff? Look at OSM. Google Map Maker. And while Google may have hundreds or even thousands of members of staff working on maps how many are (or have ever been) actually involved in editing the map?
The core data in Maps is fine. Sat Nav works brilliantly and is vastly superior to Google maps. The problem is POIs and the search engine.
POIs - lack off, location and prioritisation. Clearly there was a huge **** up when they imported the POI data. In some areas it seems as simple as they used wrong coordinate system. Basic errors but this is all relatively easy stuff to fix. Once Mavericks is launched, the 10.9 app will probably gain more sophisticated controls like OSM, Google map maker etc. Judging by the comments in this thread the search engine is vastly improved in iOS7 (and no doubt will continue to improve).