Primarily what is the expense for being squarely in the mix with a more than competent TT array for one, and secondly will the vinyl cut of the exact same digital track ALWAYS be received as noticeably better, if all else in the system is ‘virtually’ the same?IMO, if the second Q is NO. I’d not wish to spend one thin dime on a TT phono setup. Ever. There would be no need.I find that in most cases the LP is going to sound better if the LP playback rig is competent. There are a lot of variables in the playback, but one variable is not which is the recording itself so let's talk about that first.
Most CDs are compressed as there is the understanding it might get played in a car. LPs, even if made from a digital source, tend to have less compression as there is no expectation of automotive use.
In the heyday of the LP, many were compressed simply because the process was expensive and less engineering time is needed if a bit of compression is always used. That is not the standard practice today nor was it the standard practice with older jazz and classical LPs.
With regards to playback in a very small nutshell:
*) the ability of the arm to track the cartridge is far more important than the cartridge itself! You don't have to go super expensive to get excellent results **if the arm is able to do its job**. This cannot be emphasized enough!
*) vibration and damping in LP playback is pretty important; the mounting of the platter bearing must be rigidly coupled to the mounting of the arm and the whole thing should be dead. In addition there should be no slop in any of the bearings employed!! This prevents coloration, since if there is vibration the pickup will be unable to pick it up if it is moving in the same plane as the platter and at the same time. One excellent example of a 'table that achieves this is the new Technics SL-1200G. You can see that outboard arm pods do not.
*) the loading of the cartridge will be important if its a high output moving magnet. The loading prevents 'ringing' in the cartridge, which is distortion.
*) The loading of the cartridge will be unimportant if its a low output moving coil, **provided the phono section is stable** and immune to Radio Frequency Interference (This is because the ringing of low output moving coil cartridges occurs at Radio Frequencies). If the phono section is immune to RFI, an additional benefit will be that ticks and pops will be less audible. IOW phono section stability is a lot more important than most people realize. Nearly all phono sections in older Japanese receivers made in the 70s and 80s are unstable, so nearly an entire generation of audiophiles has grown up assuming that it its an LP, there will be ticks and pops. The point is they don't have to be there and a lot of them are made audible by the phono preamp.
As a footnote, if the phono preamp is unstable, cartridge loading will be important and audible, but even if loaded properly, the ticks and pops will still be there.
*) the platter pad's job is to absorb vibration in the LP so it won't talk back to the pickup. It is also important that the platter be damped (the new SL-1200 has a damped platter but a terrible platter pad; the latter is easily replaced). If the platter pad is harder than the vinyl, it will be bright and will impose a signature. A pad that is too soft will as well. My inclination is to go with the harder platter pads if they offer platter damping properties as well- that's a pretty good compromise.
I find that bass is more palpable with the LP than digital playback, and there is more detail combined with a smoother presentation. Occasionally you find an LP that sounds no different than the CD; as best I can make out these are made from the same source as the CD.