Why is 2 Channel better than multi-channel?

I should add that in many cases mono has better fidelity than stereo 2ch.
I do collect old mono records for their outstanding sound quality of the golden era.

It's pretty logical and simple: Before the digital technology all recording engineeres needed is enough space and recording speed to place every detail of the live music onto the tape. Thus, 2ch recorders benefit with channel separation and amount of information stored per one channel on the magnetic tape to the multi-channel recorders. Also most of the professional recorders are using thick tape for the same reason. Mono recorders/reproducers are able to get maximum possible information(that's why I love mono recorded music)
Even in today's digital technology it does make a sence to still produce 2ch recordings guess why?... the same reason. Better channel separation and more information(bits) can be fit onto one track. Digital signal is nothing else but high analogue freequency with the phase shifts that we call digital samples.

To tell the truth I love 1ch over 2ch. I always prefere to buy mono version of a record and might be planning buying mono cartridge when I accumulate large enough mono collection.