What's that number? How did you arrive at it and why?
My Chrome binaries are about 700MB on Mac and 500MB on Windows. Is this below or your line, or are they actually in trouble as soon as they're extracted?
My point is just that it seems there may be an arbitrary limit here that may not be the same for everyone (and 90% of users are nontechnical and thus couldn't give an answer whether 4GB is "worth it" for whatever the features are). Rather than add another whole ecosystem of "Cancel or Allow?" dialogs I'd rather operating systems did a better job of letting users put piggish applications on a strict space budget. Most of the apps on my phone are storing half a gig of "stuff" (called "Documents & Data" but not itemized, and even apps that have none of my 'data' such as browsers), which I can't force them to dump even in an extreme emergency. I can only delete the whole app.
I'm talking about Apple platforms as examples because I use those a lot and with their epic stinginess of SSD, anyone who doesn't pay $400 more than the base model will exhaust their storage within hours to months.