I love this question, and really like the different points of view and it’s solely depends on the situation you are in and what you want to do with it or without it.
Pivoting is about product/features/usability/demand/value, so I think about this in terms of customer/market feedback. As a believer in lean teachings, you run towards signs that lead to pivots, or validate why not to.
Sticking is about operations/execution, so I think about this in terms of how easily can we overcome the typical road-bumps a start-up faces, what changes do we need to make to our burn / projections / schedule / team / etc. to get to where we are going (assuming that the previous point about product-market fit has been addressed)
Quitting, logically, comes after the first two points, an requires a balanced approach. The tension comes from “never give up”, “live to fight another day”, and “would I put my own money in this?” or opportunity cost. I admire people who quit decisively, as opposed to quitting because you are dead. If you have raised money, both Sticking & Quitting should be items that come up with your investors / board members (assuming you have good ones), while Pivoting would come up with active BOD members (not all investors get into this level of detail). I think quitting should be guided through honesty / integrity with yourself, your team, and your investors.