A few points to consider. 1)Others have pointed out that most current reissues/remasters/repressings are sourced from a digital file. 2)Original pressings may be compromised in a few ways. Both points are related.
1) Moving to a digital master file is ultimately cheaper for a record label. Tape deteriorates over time, and each pass through a deck accelerates deterioration. Better to create a new master that will not change and can become a new baseline. Keep the tape in a climate controlled vault, then use the digital copy for all future reissues, without any deterioration of the baseline. And a digital file can be sent virtually if needed.
The problem is the nature of the digital copy. From carefully reading reviews, and keeping my ears open, it has become obvious that very few digital masters are high-rez. It seems counterintuitive that one would not use the best possible resolution to create a new master file, but most labels are content to use 16/44 or 24/48 resolution. Very few use 24/96, and fewer still use 24/128 or higher. Digital will always be the parabolic curve that approaches but never quite touches the horizontal line of analogue. However, high-rez digital comes very very close, and in some applications may be virtually indistinguishable from analogue. But 16/44 or 24/48 ? You CAN hear the difference on a system of at least medium quality.
2) Back in the day LPs were pressed to ensure playback by the maximum number of people. Do you press to accurately reproduce the master tape, understanding that very few people owned a TT system that could actually play the LP ? Or do you press to ensure that a teenager with an all-in-one system, or someone's hand me down from 1955 can play the LP ? Labels want to sell LPs, so you know the answer to the above question. For this reason, it is possible for a reissue to sound better, in some cases much better than a regular pressing. Original Mobile Fidelity, Half Speed Masters, many Japanese pressings are proof that the master tapes contained much better sonics than what a commercial LP offered. So the expectation is that a new "premium" reissue should sound better- the potential is there. But see point 1 for the reason why this is often not the case. Yes, you get a darker background and tighter bass. But the tighter bass also sounds more mechanical. Treble response may be cleaner, but you lose extreme overtones and some sense of air and space around the musicians. Shoddy 16/44 transfers can make cymbals sounds like rustled tin foil rather than carefully tuned brass discs.
1) Moving to a digital master file is ultimately cheaper for a record label. Tape deteriorates over time, and each pass through a deck accelerates deterioration. Better to create a new master that will not change and can become a new baseline. Keep the tape in a climate controlled vault, then use the digital copy for all future reissues, without any deterioration of the baseline. And a digital file can be sent virtually if needed.
The problem is the nature of the digital copy. From carefully reading reviews, and keeping my ears open, it has become obvious that very few digital masters are high-rez. It seems counterintuitive that one would not use the best possible resolution to create a new master file, but most labels are content to use 16/44 or 24/48 resolution. Very few use 24/96, and fewer still use 24/128 or higher. Digital will always be the parabolic curve that approaches but never quite touches the horizontal line of analogue. However, high-rez digital comes very very close, and in some applications may be virtually indistinguishable from analogue. But 16/44 or 24/48 ? You CAN hear the difference on a system of at least medium quality.
2) Back in the day LPs were pressed to ensure playback by the maximum number of people. Do you press to accurately reproduce the master tape, understanding that very few people owned a TT system that could actually play the LP ? Or do you press to ensure that a teenager with an all-in-one system, or someone's hand me down from 1955 can play the LP ? Labels want to sell LPs, so you know the answer to the above question. For this reason, it is possible for a reissue to sound better, in some cases much better than a regular pressing. Original Mobile Fidelity, Half Speed Masters, many Japanese pressings are proof that the master tapes contained much better sonics than what a commercial LP offered. So the expectation is that a new "premium" reissue should sound better- the potential is there. But see point 1 for the reason why this is often not the case. Yes, you get a darker background and tighter bass. But the tighter bass also sounds more mechanical. Treble response may be cleaner, but you lose extreme overtones and some sense of air and space around the musicians. Shoddy 16/44 transfers can make cymbals sounds like rustled tin foil rather than carefully tuned brass discs.