I have 16 GB of RAM on my laptop, and I'm told that's relatively little nowadays. Even after the OS's 2 GB cut, I can run 35 applications that use 400 MB each. I don't even have 35 applications that I care about. (and I'm certainly not going to want to run more than, say, three email clients)

RAM usage at that scale might not be desirable, but any engineer knows that it's the result of a tradeoff where the other options take longer to develop. I would rather have an application that uses 400 MB now than a slimmer one in several years, or one that uses less memory but is extremely slow in some corporate environments (like older Outlook).

(please don't respond to quibble about the napkin math)

No quibble, but you'll have to pry classic Outlook from my cold, dead hands... :)