The auction that you pointed to actually is reflecting the real market value of that lens.
Yeah you aren't the first to say so.... guess so just seems awfully pricey first for just an A and also for just a "normalish" 135mm
If it were real wide or long (like 300+) and still fast I could much more see the cost factor.
But with regular 135's (even true Pentax SMC's and stil 2.8 or better) going for maybe a $200 high (usually much less).... is it REALLY 7 or 8X better IQ????