I don't know why but i seem to be obsessing way too much lately with my axes.
-80s Tune Bass Maniac
- Steinberger XL2
-MTD Beast
I love all three to death and took me years to find all of these. The mystique of the rarity and them being discontinued seem to lure me away from all other awesome possibilities out there but somehow seemed to win the race in the final round. Can anyone else relate to this?
First, to address your primary question, "Why am I so obsessed with discontinued/rare basses??". I think the answer lies within the end of the question…
"discontinued/rare".
It reminds me of a line from one of my all-time favorite movies;
"You and I are merely passing through history. This…this IS history!"
Second, can I relate? Hell-to-the-eff-yeah! The first bass I ever, ever wanted turned out to have been discontinued a few years before my search began. But with some persistence, a lot of fruitless calls and emails, and not to mention a creative way to scour the web, I finally found
"My Sexy Beast"! 
Eventually, I even managed to get the whole trifecta! So what if I don't even play six-stringers! Call it out for what it was…a fairly inexpensive birthday present to myself. Besides, it looks smokin' hot and it'll be nice to have around if any of my friend's kids want to learn on it.
And then, there's the recent, untimely demise of Fender Japan. The thought of a world without Aerodynes is like a year without sunshine!

But rather than just sit back and watch the ship fade away into the distance, I jumped on a listing for something that turned out to be much more rare than simply being discontinued. After doing some research
(many thanks to archive.org for giving me the tools to do it), I found out it was a 2008 Limited Edition bass. Some ancient, Japanese Luck God must've been lurking in the background during all of this!
So what if it's afflicted with the classic "Fender G-string Dead Spot"! It's super-rare (on any continent), sounds great and looks even better!!
I wanted a Fender Blacktop bass, but had picked up a Warlock bass in the meantime. I was deciding if I wanted to keep the Warlock or get a Blacktop, & then I discovered that the Blacktops had been discontinued. Well, that sealed the deal & I bought a used one as fast as I could.
Same here. I bought a White Chrome Pearl Blacktop Jazz body from a local TB'er to go along with my black model for exactly that same reason. And to further the "discontinued" groove, once I get an appropriate neck for it, I plan on turning it into it's own little tribute to the '80s-era Fender Japan Jazz Bass Specials (much like the Duff-sig model).