Sounds like there is a need here to set the record straight, if you will pardon the expression :)
first:
The reason for the 14" transcription LPs and 12" tonearms to play them came from a time when live radio programs and performances were recorded, mastered, and stamped to send out to radio stations all over the country. A radio station could easily stamp 100 or more transcription LPs and send them out overnight, where 100 tape duplications would have taken 4500 minutes, or 75 hours.
There is more to it than the above- 14" lacquers are also used to make 12" records. A 12" arm is awfully handy for sorting out whether a test recording made in the outside inch is viable- if so you can proceed with the cutting method without playing the actual cut to be pressed.
Nonsense.
Assuming the source is an analog session or master tape, tape to tape copying can produce a copy that's just one lossy step removed from the original.
OTOH, manufacturing a vinyl LP involves many more lossy steps:
1. the session/master tape is played through an equalizer circuit to impart the RIAA (or other) curve
2. the equalized signal drives a cutter head
3. the movements of the cutter head cut the grooves on a master disk
4. the master desk is used as a mold to produce a metal stamper
5. the stamper is used as a mold to produce a vinyl LP
Further, additional lossy steps are required for the consumer to play back the LP:
6. the stylus must track the modulations in the groove
7. the cantilever (which is never perfectly rigid, and which pivots imprecisely within an elastic suspension) must reproduce the movements of the stylus at the armature end of the cartridge
8. the cartridge converts physical motions of the cantilever to an electrical signal
9. the signal is reverse-RIAA equalized
10. the signal is amplified back up to line level.
Only now is the signal compable to the one coming from a playback tape deck, i.e., suitable for the line level input of a preamp.
Tape reproduction and playback can involve as few as 2 lossy transfers (record/play back). Vinyl reproduction requires at least 10.
Direct-to-disk LP recordings eliminate step #1. Even this small reduction results in audible increases in resolution, s/n ratio and dynamic range... which proves the point: every lossy step impairs realistic reproduction.
Whether any particular consumer tape setup is as good as a particular vinyl setup is a different question. Whether the cost of tape copies is affordable or the hassles worthwhile are different questions still. But tape is the inherently superior medium.
There are a couple of points to be addressed here. Tape and LP both require EQ during record and playback. The problem here is that the tape used in the home is rarely a copy of the master, usually its a copy of the working copy; IOW most tapes played by audiophiles are 3rd generation copies, not 2nd generation. LPs are usually made from the master tape if the LP was pressed in the same country as the tape was made. Although not a common practice the LP can be made from a 2-step process, which is often used in short runs.
Now what Mattmiller said that got this comment from Doug was the tape will never surpass LP in resolution. That is actually a fact (although rarely realized). The LP has much more capability (in this case defined as lower distortion, wider bandwidth and wider dynamic range) than tape. What LP does not have is convenience in the recording studio! This is why tape is used- you can go back and re-record it. If you mess up while doing direct to disk, the lacquer is so much junk. This is why direct-to-disk is unusual.