Many of the "personal Luxury" cars of the last four decades have led their contemporaries into the leagues of collectible automobiles. By collectible, I don't mean they command "mega bucks," but rather they a following that cares about finding and buying good ones for the purpose of personal enjoyment.
I don't think it is a major mind twister to see why many personal luxury cars have become collectible cars. Two seat Thunderbirds as well as early Buick Rivieras, Cadillac Eldorados and convertibles, Olds Toronados and Starfires, sixties and even seventies Thunderbirds, to mention a few, have all been collected in recent years. It would seem to me that some twenty year old personal luxury cars from the nineties would begin to be collected both because of nostalgia, but in some cases because of their attractive design and performance. I would think the Eldorado and the Riviera of that period along with the Seville would begin gaining a following among enthusiast and collectors.