Many open source developers start with intentions like "advancing the state of the art" and over time become disappointed because others build businesses and profit off of their creations. The intention at the onset wasn't to make money, and continued investment of time and money into OSS should be weighed against the original intention.
We are elated when we find others using open source SheetJS libraries and code in their profitable business applications. Others may regret and wish they didn't open source, but you don't know how things would have played out if you didn't open source. The yardstick we apply to our open source contributions is whether we're advancing the state of the art, since that's why we entered the space in the first place.
https://news.ycombinator.com/item?id=14886481 is a similar comment that probably better reflects the opinion expressed here.
(note: we ended up developing paid offerings after conversations with @patio11 and others. https://www.kalzumeus.com/2015/01/28/design-and-implementati... discusses these points)