Where is the significant point of diminishing returns on hi-end turntable?

For me It's simple.
When the system disappears, And all your left with is a band playing 
You have arrived.

All you need is the right combination. The room itself needs to be soft. Clap and if you hear an echo it's not a good thing. I have an Audire Crescendo which which cost me $500 which I would recommend. They usually run around a grand.
   It's like owning a super car. If you buy a super car because you don't know what to do with all of your money. Then buy a super car. On the other hand if you take out a loan to buy a super car you are a fool.
   If I was to put a cap on it. I'd say you could reach the minimum requirements for a audiophile system for as little as $4000-$5000 bucks. But at that range it has to be a passion where your constantly buying and selling older used stuff to compare.

Happy listening

@mmporsche You seem to know what you are doing and how to do it.
To answer your original question, although I don't know why anyone else's opinion should even matter, I couldn't hold my head up if I couldn't complete the task with $15,000. Much less given time and the option of used equipment.

Your ears are the most important component. Developing them takes time and effort, no matter what your budget is. That's the hidden lie in that old Maxell commercial. You can't just buy connection. 

I think learning to hear is the great joy of audio, but that's just me. And anyway my Porsche is just a lowly 1980 Euro SC. Maybe I haven't gone fast enough...

@rushton @rauliruegas  I am proud to have you both as friends as you both regularly wake the conversation and set it back to where it will serve some good. 

Live music must be the reference if you focus on classical & acoustic jazz. If your music of choice is rock, "what's real" is always going to be subject to massive interpretation, so let's not even go there.

Listening to as much gear in as many real home type rooms is going to help you train your ears and learn what "takes you there" -- back to that reference where the hairs on the back of your neck stand up and you feel the goosebumps. Get in a local audio club, people! When gear synergy & room setup work for you, take note and figure out why it's right FOR YOU. This experience will go a long way to defining each of our own definitions of the point of diminishing returns. That won't be a dollar figure! Cheers,
Spencer

Guys,

I have written extensively on the fraud of vinyl in today's modern audio world.

If 65 dB (1/2 that of say a snare drum) and that "warm sound" (meaning 2nd degree harmonic distortion) is good enough for you then vinyl is your choice. You get a low resolution, high distortion format that is dead.

Note: CD is dead too as its not enough digital material to make a truly "analogous" reproduction of music compared to a 24-bit 96 (or 192) kHz file which is in effect a direct copy of the master tape. YES PEOPLE - you can buy meaningful music in volume at master tape quality. HDTrack.com and elsewhere. 

You can buy all the cool gear in the world here on Audiogon.com thus essentially creating an audiophile Ferrari. The SECOND you spin one lame-ass, low resolution LP and you've fueled said Ferrari with 50 octane gas. I will take a pair of $600 Elacs, a small Elac integrated amp, a small subwoofer and some 24 bit files in a CHEAP system and blow one of these Ferrari's out of the water in term of performance while saving TENS upon TENS of thousands of dollars. Buck up for better gear and room acoustics - and the experience only gets better. A LOT better. I am just saying you can't fake master tape quality audio as a starting point people.

Most importantly, and I get punished for saying this by readers and even some advertisers, the audiophile hobby is literally and figuratively DYING. The people who design the gear, sell the gear and who buy the gear have made it a nerdy, one-person sitting in a dark room hobby and its not growing. The so-called and unfounded resurgence of vinyl is promoting the sales of music on a physically degrading media in the used domain. It speaks in NO WAY to the future of the format and its future audiences who listen to tons of music - but more streaming and on their phones. CD is a dead format but it sold 100x more volume according to SoundScan last year. New vinyl in its entirety is a "multi-platinum" format. That's right EVERY DISC SOLD sells about 3m units. EA Sports can sell more Madden Football in 30 minutes than all of vinyl in an entire year across all format. People want high resolution over retro tech snobbery.

I ask you to consider the way you look at your system and its future. Do you listen to music in its highest resolution? Do you stream every CD known to man for $20 per month (yes, Tidal is pretty cool and would only be the BEST if they went HD via MQA) or are you stuck in the past? If you are stuck - consider this post an invite to change. Its not too late and there a lot to gain including making ALL of the investments you've made in your system sound EVEN BETTER.