Black metal should never be extremely popular or known, because it will definitely result in even more horrible bands than there is now.
You can make that argument about any style of music that isn't popular. The only difference is that black metal is a genre that prides itself on being underground or obscure for-sake-of being obscure - it isn't better than any other genre and it's is a lot more 'accessible' than it's thought to be. Not to mention popularity is increasing all the time, and considerably within the last few years.
Also, don't you find it rather ironic that diehard fans, who are so opposed to the genre gaining any attention, spend plenty of time discussing the latest, most obscure kvlt bands online thus promoting interest in the genre? Just had to rant, I'm tired of the kvlt mentality...
As for Varg, I thought he said he was more likely to make an album that was in the vein of "Hvis Lyset Tar Oss"? Whatever the case, I doubt Varg will make another black metal album. I wouldn't be surprised if he was disgusted by the fact that so many bands had blatantly ripped off his syle of music to this extent and for that, decided against doing so - similar to his shift of opinion on the genre years ago.