Google Earth does not show latest (even 4 Years Old) structures, why ?

+ I don't think that your Google Earth is out of date but however download the latest one from http://www.google.com/earth/download/ge/agree.html or update from Help Menu.

+ It might would happen that which area you are searching for is not scanned for a while.

+ May be you are working offline from last four years :P

The image shown by the Google Earth is only a cache of the image.these pictures had been taken long time ago and it is not a real time image.Only by updating you can fix this to a certain extent.

That is because you don't have the latest update, or google earth has failed to update. I haven't used it in a while but i think you might want to update it. In that case, Google is your friend!

this is cause when google first took pics of the earth it was 5 yrs back now in 2yrs u will get a update

It has to take time to update its database. And if your city is not a popular one, then it can take more time. Better switch to wikimapia.com. It better than google.

It has to update you can't just get live footage of the whole world

It's because they literally drive a motor vehicle and take pictures.

you install newer version of Google earth

or reinstall it