I collect multiple players too and I actually had that recently happen to me. I had just dropped some $$ on a Melo patch auto, then BAM the next day a DeMarcus logoman /5 shows up on eBay. I wasn't impressed to say the least and now, with Melo being a Knick and all, I sort of look at that Melo patch auto and think what could have been lol.
On a serious note now, The different sports draw, I think, a different sort of collector. I get the impression that a lot of bball collectors build their PC around individual players rather than a team. My PC is built around my team, the Broncos of course and my collection starts in 1988. I would not be interested in any cards prior to that and my collection does not change when players come and go, I mean if Darren L left the club tomorrow and signed with Parra I would not chase down any highend cards that come out of DL in parra colours because he is not part of my team.