Earlier quoted context omitted.
You don't need to invoke social narratives and consistent behaviors to justify honoring sunk costs. Sunk costs are often a predictor of a developed position. For example, you spend 20 years in advancing in field and then worry that you might not like it that much anymore. If you avoid leaving the field purely because of the sunk time, you are honoring a sunk cost. If you avoid leaving the field because your 20 years…
For sunk costs, you are supposed to consider your all options including the sunk cost project. For your example your options might look like: * Stick with industry, 0 year lead time, no cost, possible sadness, low risk * Slight change, 2 year lead time, $20,000, moderate happiness, medium risk * Vast change, 10 year lead time, $100,000, unknown happiness, high risk The fallacy would be giving the first option some so…
But when we have sunk costs, we really have a past investment that we have an unknown return upon-- and we're deciding whether to abandon that investment.
If we've made a substantial investment, it can make sense to have a bias towards avoiding actions that definitely invalidate that investment-- a bias towards inaction.
It's rare that a position presents itself where it is completely clear what the future value of different tracks is worth so clearly.