No it does not make sense for Menzoberranzan to be so prominent, but it's the most popular, so it gets the mention over the much closer (and more relevant to the BG saga) Ust Natha. Ongoing theme with the drow the past few editions, sadly. Menzoberranzan gets so much focus over other potentially interesting cities that it bends space and time, getting retconned into being more central and more powerful, with comparable cities being destroyed, ignored, or retconned. It's not actually even clear right now if there *are* any other (evil) drow cities in Toril besides Menzoberranzan after that whole 'udadrow/lorendrow/aevendrow bombshell WotC dropped semirecently.
To Larian's credit though, there is a single mention of another drow city in the game right now. Sshamath is mentioned by one of the dead drow cultists if you use Speak with Dead on him. Granted, from what he says, it seems that Sshamath is/was (it's unclear if his phrasing 'before the absolute' refers to him or the city as a whole) more of your standard Lolth-worshipping female-dominated society...when it used to be well known as a non-religious, male-dominated Magocracy. So either a retcon or an error. Better than nothing, I guess.
