Is it worth spending $10k on CD-only player today?

Yes. I would if I had the scratch, a larger income, or if I was more established in life. SACD isn't going anywhere unless you listen to classical music. I do, so I would likely consider the Meitner stack. I would not consider something with compromised redbook playback. I'd rather have a dedicated rebook player in that scenario. And I feel that is the crux of your question. Redbook is too ubiquitous. And as such would not fit morepeople's definition of 'obsolete.' Though there are many slight meanings of the word.

Although SACD and DSD is superior to redbook, redbook will likely be obsoleted by mp3 or something similar. And by something similar I mean something distributed as a computer file - either hi-rez (not likely) low-rez (more likely).

marco, drop one of the zeros and you'll sound like the unwashed, non-audiophiles. (what $1k for a cd player? R U nuts??!?). same argument (diabribe?), different values no?

I agree right now I'd maybe do a ca.$3k player and have some mods done do it, and spend the other $7k on music or something else like a transmission for the car, or a stereo for the jeep. Heck, I'm having a hard time upgrading from my $300 DAC. But I can see where $10k players have their place for the select few (those with means and those for whom that level of quality matters. which again is a pool of very few). I wish I was one of them. Though I am not.

The one thing for me that helps put mega-buck digital in perspective was reading about the listen tests at Albert Porter place with megabuck digital, his Lloyd Walker table, and his lowly Sony 9000ES. But I think that's mainly due to the fact I can't afford the megabuck rigs so I appreciate justification that one may not be worth it for someone also into analog.

Maybe you are right though. For most studio and electronic music we'd likely have a hard time distinguishing a $3k from a $10k player. But maybe the original poster mainly listens to unamplified acoustic music recorded in a live space (read classical, jazz, or folk/ethnic)?