To be completely honest, even if I didn't have a single paying subscriber I would still happily pay to host it out of pocket (and for a long time, I did) because it is the perfect tool for my own needs and it is so deeply integrated into all written knowledge consumption in my life[1] - I will use it until the day I die (and then my wife will open source it).
[1]: I use it to save comments from HN, Reddit, Twitter etc., I use it to save highlights from web articles, I use it to save/import my Kindle highlights, I use it to highlight parts of newsletters in my email inbox - the list is endless
