Hey Kristoff, I've wondered the same about games ending with unclaimed prizes, as it's a vexing question. I do think though that missed wins on players' part is a huge part of the answer. Missed wins happen most often with number matches, so tickets with a single number match are more prone to be mistakenly discarded as duds compared to ones with multiple number match wins, and especially symbol wins.
To test this I looked at the $30 FRM data. The data shows a high correlation between win levels with high single number matches and unclaimed prizes. Please see the data table and supporting graph.
Make no mistake I'm not a big fan of many FL Lotto policies, esp when it comes to their lack of decrementing avail wins for lost/destroyed/stolen tickets, but in the end I'm afraid the tendency for players to miss a win and, alas, discard a winning ticket (even jackpot size) still looms large. The ticket win App might help quite a bit, but only more run time with it being available will tell for sure.
One note: The analysis assumes that the Money Bag win section is equally distributed among all win levels (so was equally conspicuous).
Here's where the rubber meets the road...please, ALL, do be voracious if I'm off in any of this analysis and/or should additional info be considered ...facts plus healthy dialogue are what makes this thread especially good