[happytoexplain]

A. You're assuming they are largely the same people by extrapolating from your observations. It's impossible to actually know.

B. Your two examples provide different things. This is like saying it's OK to include any old multi-megabyte dependency if a site loads a couple mb worth of images. There's no reason to stop considering the size of the small parts just because you decided you need some large parts. Things add up - that will never stop being a useful thing to remember, in any context.