At what price point do I run into diminishing returns on an MC Cartridge?

  I disagree that price has Nothing to do it. It just doesn't have everything to do with it which I recognized prior to posting.

There is absolutely nothing in cartridge design that can cost $5k or $10k, some cartridge manufacturers selling their new models even for higher price. This is what i mean, their price tag is just their decision to serve small group of reach people. That's it. I don't want to say their products are bad, some of them are very nice, but the price is overestimated for marketing reason only. 

I'm impressed with your experience, and suggestion to look for older makes when analog was in its prime, but you offer no suggested leads. A little help...?

All exotic cartridges with the most expensive cantilevers, diamonds, special cartridge body ... etc ... are already made in the 80's. Even the rarest of them in NOS condition are still under $2k max and they are amazing. The reason why you or me are willing to change a cartridge is the sound flavor that is the most pleasant for our ears in our system/room. If you can't find the most involving $800 cartridge then maybe the problem is not the cartridge, but something else in the system. Because i know many cartridges in this price category that just perfect and better than my ex $3k or $5k cartridges. But i have many tonearms and a few phono stages to experiment with cartridges on two turntables with 4 tonearms. Also i like MM and MI cartridges better than most of the MC cartridges. 

If you need an example of vintage LOMC then look for Fidelity-Research FR-7fz or Miyabi for heavy tonearms. If you want unique design then Victor MCL10 (direct couple), Ikeda 9 III (cantilever less model)... On the cheaper side there are Dynavector Karat 23RS (Ruby cantilever) and KARAT 17D2 (Diamond cantilever), Klipsch MCZ-10 Ruby ... 

If you want to spend less with stylus replacement option (that you can change by yourself) then definitely vintage MM like Audio-Technica AT-ML180, Stanton 980 or SC-100 WOS, Pickering XSV-4500 and 7500. Also Grace LEVEL II with Ruby, Sapphire or Boron cantilever (they made so many optional styli). Victor X1II is another killer ... 

P.S. Some of the reasonably priced new LOMC are Miyajima (several models) and Audio-Technica ART-9        

chakster
Wow.  Thanks for taking the time.  I have some studying to do!

edgewear
Fantastic reference on the Halcro Hear my Cartridges thread.  Crazy chock full of data!  Thank you.

With all my respect to our Halcro i would never chose a cartridge based on other people system by listening to it over youtube mp3 sound video link. It may help a bit, but i think you can also go to the wrong direction if your reference is his (not your) system and mp3 file recorded with a mic in his untreated room. If this way of choosing a cartridge could be the best them life of audiophiles could be much easier. His cartridge in your system will be completely different and it depends on your tonearm, phono stage, your speakers and your room. Also your personal preferences in sound. However, he’s got some very nice cartridges indeed like many of us.

Regarding the internet surfing you can listen to Kenrick Sound online and i bet you will like all his speakers and digital playback from iPod, lol. The reason is his multi-thousand dollar microphone. Everything is just great in his video, but in reality it can be different.   

@normantaylor. Price and cartridge desirability are not necessarily connected, IMO. What has been mentioned above is certainly very true. A lot of the results will be highly dependent on the ancillary gear and room. Another variable is set up expertise. For example, with Lyra cartridges, any number of differing opinions can be had... because the set up was not as exact as this line demands.. resulting in naysayers who attribute what they hear to the cartridge and NOT the real issue... a faulty, or less than exact set up!
Is there a “sweet spot” in cartridge design and price point... probably depends on your musical expectations and other biases. Personally, I think your Kandid and it’s sister... the Kleos,are probably about there.IMHO.