Why can't the size of updates/downloads/apps be shown in the app store?

You mean like it's shown here:

or here ?

The info is there, you just never bothered to look for it.

Note that these are user forums. You aren't speaking to Apple here. But the App Store provides the file sizes as you can very obviously see.

Well, actually, they were right in some circumstances. This is a major pain for me too. If you look at updates, Apple appears to have removed any information about download size. It is a major exercise to go and Google an update, find a related web page, and then you may be able to see how big it is. Your examples are spot on for apps, but for system updates, sizes are typically not shown - at least on my system. In earlier revisions of OS X, the size of software updates was shown up front.

Just so we are talking about the same thing, here is my screen grab (hope I didn't reduce this in size too much to be legible):

That information will appear in the download progress bar when you click on Update.

Send Apple feedback. They won't answer, but at least will know there is a problem. If enough people send feedback, it may get the problem solved sooner.

Feedback

Thanks Eric and Kappy. I have sent Apple feedback on this issue because I think it is pretty annoying.

I am not going to launch an update then check the size in the progress bar, because when I have to pause it until my next appropriate off peak download time, it often fails. I had this happen recently after pausing downloads for apps and I had to re-download each app individually from the store, as the download would not resume correctly. Granted this may not always be the case, but checking the size by starting to download it is not a great solution for me.

Ivan