R2R does not suffer RIAA Eq. and the lowest bass registers / octaves are in stereo - unlike LP which are in mono.
This statement is incorrect. LP bass is mono **only if the bass was out of phase** in the original recording. Out of phase bass can knock a stylus out of the groove, but is something that only occurs if the recording engineer isn't careful when making a multi-channel recording- for example bass guitar notes being out of phase with kick drum.
The processing that is done in this case (if the processor is used at all) causes a passive circuit to make the bass mono below a certain frequency (usually about 80Hz, since bass below this frequency is the problem area and is heard by the human ear as omindirectional), **but only for a few milliseconds** until the bass event has passed.
R2R has EQ very similar to the RIAA in the bass region. Because of the requirements of gain, usually the tape EQ cuts off at a higher frequency than LP equalization- 30Hz is typical. Since we have enough gain to work with low output moving coil cartridges, when we set up tape EQ in our preamps we can cut off at 16Hz, but this pretty unusual.
Tape of course has EQ and its really not dramatically different from the RIAA curve- which is why its possible to build a preamp that has easily switchable EQ for tape and phono. Saying that tape doesn't suffer EQ is ridiculous.
One might keep in mind that tape is used to make a recording because its easily erased and edited; lacquers are not. However if you have any LPs made from R2R, you can hear when the tape is started at the beginning of the LP- the noise floor increases. LP is the mass media for the simple reason that is has wider bandwidth, lower distortion and lower noise than R2R, which makes it possible to encompass the R2R recording.