I think quantity is REALLY important but not 100% better than quality. The quality is important too, if not you will not make even 1$ a day. If quantity is his point, the question is not "why not make 1000 of em?", the question for you is "why not make 1.000.000 of em"??? to get 1.000.000$ dayly. You can easyly make a million of them using spam softwares but if you don't have at least a little of quality i'm sure you will not make a million dollars dayly.
I don't like your attitude towards him. He has already stated in a post title that screenshot is for inspiration. How greed are you by bashing on him for not telling you details about his work? Congrats for OP anyway. I never make such a kind of huge amount per day but hope I will.
When I clicked this thread I was half expecting it to be somebody who didn't speak english very well pushing whatever lame eBook that "led to their great success" so it could be a lot worse. However I do kind of agree with MakeADifference. Personally, I think its fine to post your daily earnings, only as long as the post has some other purpose though. If you were to ask for strategies for growing it or had some tips, this post might be interesting but to many of us it appears to just be gloating and from some of the people I've encounted, $100/day is lunch money (I believe Shoemoney posted once that he needs to make $2k/day just to pay his staff. Of course its easy for me to say this as I'm hovering around $5/day currently. Bottom line, there's enough junk posts on DP as it is, post something useful.