As Art pointed out, it's just the nature of the hobby. At this point, I don't think anyone really knows how or why many of us have such over abundant "collections" ( for lack of a better word Jonathan ).
I remember even as a young lad some time around 1957, as we had just moved to England, my Mom had decreed, " No more 'new' models till you finish what you already have." I can remember a Lindberg X-3 being one of those kits. A big deal as we had just come from Edwards AFB. And as Art said; saving up the fifty cents ( I remember that as well, 2 weeks worth of lunch money) to buy a Comet B-45 kit from a friend (?) at school. Had to have what was flying on base at the time. in 47th Bomb Wing colors, same as the base, can't beat that. Just thought of something else, getting the ill gotten gains into the house. Being 1/87th scale , not too hard. Same as now. The next "Gotta have" kit was also from Comet, their B-66. After all the 47th was converting. Looking at the box art, this aircraft was probably just coming our way from Hurlbert field in Florida.