I think the most important part is sutainibility, you mentioed about @broncnutz and I have been a regular follower of him since Aug 2017 and my observation for him is that he was having 55K SP during those time and later in December added some more now he is having 0.1 million SP.
But let me tell you that he got his fan base beacuse of his generosity and over time he really build a massive follower base and geneerally who are having a huge SP, have got the upper edge to build a follower base na dit is easy in steemit.
But the main issue is that sustainability, you have to sustain to those level once you reached and after you reach that level, it requires more than the SP amount to sustain at that level.
But I do find you @talanhorne as generous as well.
Thank you and Have a great day.