Xan13x, alas it's the result of general consumer supply & demand,
mixed with the convenience for manufacturers of making mostly
1080 screens. When I hunted for a 2560x1600 screen last year,
I was shocked at the prices, because the same thing has happened
at 2560, ie. the market has narrowed in on 1440 height instead of 1600,
so the latter are now expensive (assuming one can find them at all),
eg. the Iiyama XB3070WQS-B1 is about 700 UKP, and the HP Z30i
is more than 1000 UKP.
At the least one positive from all this is that good 1200-height IPS
panels are now much more affordable. My first 1920x1200 IPS was
an HP LP2475W which cost about 450 UKP, but today the Dell U2412M
costs less than half that much (is the Dell better? Well, yes & no,
different feature set, etc., but the screen is nice).
I gave up on finding an affordable IPS 2560x1600, and meanwhile it
was obvious review sites had settled on 1440 height anyway (a few
years ago many sites were still testing wtih 1600 screens, but not
now), so I bought a Dell U2713HM instead which works pretty well,
except for its irritating resolution limitation over HDMI (watchout for
that if you buy a new screen, some models only support their max
res via DVI or DP - the Dell I bought can't do more than 1080 via HDMI).
Ian.