I think it's more of a case of the kids wanting to keep a few things to remember their parents by, rather than keeping the whole lot. The other thing to consider is that some people are more sentimental than others. One person may dump everything, another may keep everything, but most will be somewhere in between.

Granted e-products are much less sentimental than their mass produced physical counterparts. Likewise, those mass produced physical counterparts are much less sentimental than something they created personally.