About the pen name and no self promo: The theory is that the best way to spend your time is writing the next book, and that each time a book comes out, all your other books get a little bump. So instead of promoting this one, work on the next. This works for me because I'm not convinced that self-promo does much good in the long run and (here's probably the true reason) I don't want to do it.
With traditionally published books, where you have limited shelf life before your book is declared dead, trying to get it to move makes sense to me.
It has occurred to me, though, that only the publishers really benefit when authors play the "I'll buy your book and you by mine," because each receives so little royalties.
I think in some ways people are in more danger of quitting and giving up if they go the self published route instead of the sell-to-traditional-publishers route because you can just keep on trying to sell to a trad publisher, but if you self pub a book but don't get many sales, it can be even more discouraging. You're really putting yourself out there.
On another subject, I live with people who say, "I am not arguing! I'm not."