I think either ALPA or APA conducted a study which concluded that the break even point is seven years. If you can get to a legacy by age 58, you will make more money even if you don't upgrade than if you stayed at a regional as a topped out Captain.

So if money is your priority, then the math speaks for itself. If instead you value QOL or not retiring as an FO, then those would support the case for staying at a regional.