This particular bike was even new not more expensive as the price of the one at ebay. It's also not a collector item as the have sold thousands...
As I have seen a few beeing used meanwhile as daily bike to get to the railway station, I wouldn't be concerned about durability at all.
The bike itself was back in time quite innovative, but never turned to an very cool must-have.
The design but also technical concept was done from Arrow, a brand belonging to the bike company Villiger, together with some scientists from ETH University Zurich.
To me, this even builds on the basis of earlier research activities and the very iconic prototypes Butch Gaudi's MTB Cycletech has done with the ETH a year or two earlier.
Just look at the rear triangle, in particular the dropouts and the quite big "horst-link".