"In real life, the amount of 'stuff' you can have in your house is not limited by the acreage you occupy"

oh really? why then I can't fit 40 elephants , or perhaps a couple of big-rigs in my appartment? Xp

Ok, there are some upper limits, but I hope you know what I mean. If someone wants a house in SL which approximates or exceeds their RL standard of living, it needs to be supported by a lot of acreage so that they have a lot of prims to throw around.

I suppose you can argue that RL does this, by having cities in one place and farms (and resevoirs) far away, which results in a low overall density, but I suspect the people fussing about SL density aren't going to look at the big picture like that.