I agree, perfectly good recordings can be destroyed in the mastering process, and in fact that seems to be today's norm.
As far as ECM and 24/88.2, it would appear that only recently have some of their albums been released this way; are you sure they are not recording in DSD at this time? I just checked some of their other recent albums (Micheal Formanek, Chris Potter) in 24/88.2; they also have that suggestion of a rise in response above about 30 kHz that isn't present on their 24/96 releases from analog masters (like Jarrett's Sleeper). And even some of their recent pure digital recordings are at 24/96 (Garbarek Live in Dresden, Jarrett Testament), although it does turn out that most of my pure digital ECM hi-res is 24/88.2; I should have checked more closely. I think all the hires from analog masters is at 24/96, 24/48 and maybe a couple at 24/44.1.