I actually gave a lot of thought to this last night, when I was explaining it to some folks on a forum for one of my other hobbies (a particular kind of doll). They immediately "got it." So I started working on analogies for non-game and I think I came up with two that work for just about everyone.
For sports fans:
Think of it this way. Imagine if the owner of (your team here) decided that he was going to start a brand new team in another city. Which is fine, but you stay loyal to (your team here), which has a devoted, if smaller, following than the new team, and is profitable, though not as profitable as the new team. Then of course, we're in a recession, and people stop spending as much on sports. Both teams are not as profitable as they used to be, although both teams are still making a profit.
But the owner decides he is not making enough profit from (your team here) and decides to shut it down in mid-season so he can put all his interest into the new team! And he goes to you and says "Well sorry, I am shutting (your team here) down. Sorry about that, but look at my brand new team! Come and support that! Oh, and too bad about that season ticket you bought, no refunds. Oh, and you have to give me back all that (your team) merch you bought, you never really owned it even though you bought it. No, sorry, all you can keep are memories."
For Granny, Auntie, and Great Gramma:
In a way, these games are a little like churches; the fellowship with your fellow churchgoers, the covered dish potluck suppers, the church picnics, and the socializing after worship are very important to churchgoers--who wants to go to a church where you just march in at 10 AM on Sunday and march out again at noon and never see or talk to anyone in between? That would be VERY unChristian, wouldn't it? You make friends in church, and we make friends in our games.
Think about how you would feel if the bank came and said "Sorry, you just don't have enough worshipers at your church, we're closing it. No, it doesn't matter that you gave to the building fund for that new kindergarten, no refunds. Why don't you all just go to that shiny new television evangelist's church down the road, it's a LOT bigger and newer anyway than your 100 year old church. We're going to knock it down and put up a parking lot." How would you feel about that?