You're probably right, however i'm sure one will pop up at a reasonable price at some point, i'd been looking for a US Magician Lord CD for years with no luck but finally managed to get one when one popped up recently being sold by Cash Converters, a pawn shop chain in the UK, listed as a Japanese game.
The last Magician Lord US on ebay was last month in the UK and it went for 100 GBP, without spine card.
The last Ninja Combat US on ebay was yesterday in Germany and it went for 101 EUR, also without spine but here I'm not sure there was every one.
I'll also have to wait patiently for theses 2 to pop up somewhere at a decent $10 price :-)
But again, since when is a simple FFS US, without spine worth $149.99 !!
More $14.99 to me.