Develop a hierarchy for phono playback

The order can change depending on what components you are using and what is the overall price points a person is targeting. If a person is getting into LOMC land then I would move the SUT way up the list. 

Interesting to see two different philosophies here on whether the cartridge comes first or last.

Like loudspeakers, the cartridge does make a big difference to the character of the sound. However, that is more a matter of taste than ultimate sound quality.

I’d go with the source first hierarchy of turntable, arm, cartridge and phono stage.

The turntable if upgradeable like an LP12 could be further broken down into say bearing, power supply and sub-chassis. In the case of the LP12, the Bedrok plinth may have just put the cat amongst the pigeons. 

..."the cat amongst the pigeons."  That's a good one.  Especially since a cat will often ignore larger birds.  We say "setting the fox to guard the hen house". But what is it you wish to convey about the Bedrok [sic] plinth?

I put the tonearm first, not for sound quality, but for reliability and ease of adjustment. I built my own turntable using a thread powered external DC motor and a sandwiched bolted together pair of 1/4" thick pieces of transparent florescent green acrylic sheets I cut to shape on a band saw. They are tightly bolted together and they are screw-adjustable in a garnet plate sitting on vibration isolating hemispheres. I have a premium spindle ceramic bearing and a large acrylic platter from spare parts. This is simple so it can be fourth. The cartridge is second because it is critical. I use a moving magnet Ortofon Black cartridge because I do not accept the way moving coil cartridges cannot be repaired after they wear out in about 1000 hours of use and cost so much that it makes playing records cost more than a streaming service. Third is a simple vacuum tube phono preamp and cables that make a reliable connection that sounds best when the pins make a clean contact. 

Nice try, @billstevenson , but not practical or likely applicable.  Most purchases are budget limited, so trade offs until deep enough pockets to optimize individual components.  For instance, a quality tonearm may be similar in cost to an entry level turntable+tonearm combo.  Also, with many carts, phono stages, etc. how do you choose? At what level is acceptable? It’s not black and white.