Sadly, there isn't a museum in the world which can display more than 10-20% of its collection. I work occasionally at three different [smallish] local museums and our least favourite visitors are the ones who come in to show Cousin George the left-handed horse collar they donated 17 years ago and are appalled that it isn't in a front case. The fact that we have 16 horse collars, 14 of them in better condition and with verified local connections hardly ever satisfies the donor, who goes away convinced that we have somehow 'cheated' them by accepting, however reluctantly, their gift in the first place.
To add insult to injury, of course, not infrequently the conversation around possible donations begins with 'Well, I was going to take it to the rubbish tip but...'. One of the museums I volunteer at had wonderful wonderful artifacts given to the recently retired curator, who knew everyone in the county and never said now to a donation. This means, of course, that we have some things that the Royal Ontario Museum covets and a whole load of complete sh*t* which Jimmy 'couldn't say no to.'