The problem is that Google do most of their photographic work with airplanes - and it's very hard to fly over the Antarctic because of the horrendous weather and the danger should you need to land urgently.
It's easy to forget that Antarctica is HUGE - it's an entire continent...so there isn't good photographic imagery for much of it.
Hence most of what Google show is satellite photography.
But in their mission to "Do the best they can" with the data they have, they show airplane photography when they can - and satellite when they can't get airplane shots.
This causes one kind of "patchiness" - the other kind is caused by the fact that not all of their airplane photos were taken at the same time - some of them will be years old, some much more recent. But because the weather changes - and (especially) because the ice floes are changing continuously - you often get very visible lines between photos taken at different times.
Another problem (which you sometimes see even in photos taken over big cities and such) is that the airplane doesn't take all of the photos at the same exact time of day - so the shadows are often different and seem to "jump" as they switch images. They have a ton of software that tries to fix these anomalies - but it can't ever be perfect.
As a general rule - the less inhabited and area is, the less good photography they have to present - and therefore the worse the appearance on their web page.