Dear Nolitan: IMHO the whole subject is to understand the individual role of each analog link and its relationship between them more that the $$$$ for each one ( of course that money always is important. ) like your last post.
I agree with Syntax and Dertonarm that the most critical link is the phono stage for MM and MC cartridges. Is here in this phono stage where the cartridge signal must pass for a complex and " heavy " process to be amplified ( gain up. ) to a level that can be handle for the line stage and then to the amplifier, this is one of the important jobs of the phono stage. The other important one is that in that phono stage the cartridge signal has to be re-equalized through a inverse RIAA eq. stage to attain that the cartridge signal that goes to the line stage be with a flat frequency response.
In both of these phono stage process the cartridge signal ( always ) " suffer " a degradation ( different degradation forms: noise, distortions, colorations,etc, etc ) during the signal phono stage " manipulation " .
The main target on a phono stage is that the cartridge signal comes out with minimum lose/add whole distortions trying to preserve the cartridge signal original integrity.
But this is more easy to say that to attain that's why always is desirable to own the best quality performance phono stage we can.
In second place IMHO the tonearm/cartridge match is a crucial audio link ( together not separate or tonearm+TT like you post. ) because the same cartidge perform different in different tonearms ( everything the same. ) and we have to match the cartridge and find the tonearm that can make that the cartridge show its best quality performance.
Then the TT and tonearm internal wiring/headshell wires and tonearm IC cables as the TT/tonearm/cartridge set-up.
It is obvious that all analog links are important ( any ) and we can assess this through our each audio system experiences that when we " touch ", making tiny changes, in one analog link the whole analog quality performance change too.
As Dopogue post: +++++ " different folks, different chains. " +++++
IMHO there are and exist opinions just opinions but no absolute rules or only one " road ".
Regards and enjoy the music,
Raul.