I think it's perfectly possible that all the mint in box Victorian sets popping up on eBay have been sitting in small toyshops for years, until someone came along who recognised their potential value, bought them, and stuck them on eBay.
There are a couple of set 5315 in a toystore here in Eugene, but I'm not prepared to pay the $30 they're asking.
In the last few months I happened across three different 3666 castles all in original boxes - two in a toyshop in Dublin (Ireland) and one here in Eugene. I'd have bought the Dublin ones but for the difficulty of getting them back to London with me, and the 200 Euro Pricetag each. I did buy the Eugene one, plus a 3667 castle in the same store.
Of course Playmobil still have the capability to recreate all the Victorian sets if they wished, but they haven't, yet.