I can't recall a time it wasn't for sale - Antti Lovag went over budget to begin with, Pierre Cardin bought it with the thought to complete it and then tried to get out of it as hard as he could. HGTV did an "Extreme Homes" there in 2012. It's been on Rich People AirBnB for 6 years now. The thing that's kept it stuck is it was always being sold for spectacularly more than it was worth - I mean, yeah, incredible view, noteworthy architecture, one of a kind, provenance etc but Cardin wanted like 300m euro or something. It was $390m in 2014, then $330m in 2016, which is probably just currency drift but I'm too lazy to check. It looks like the current rate is $456m at which point the sales price is just a rental gimmick - if you can rent the thing for $1500 a day nobody really expects it to go for more than an F-35.