That's a chicken & egg argument.
If taking it off is permitted, and taking it off would reasonably increase your probability of a higher income, keeping it on is losing out on money you're 'supposed' to earn.
If taking it off is prohibited, taking it off won't cause you to earn more.
Either way, the fact that the income is predetermined doesn't have any impact on the actual halacha, it merely makes it physcologically easier to obey.
For me personally and based on my rebbeim, there is a predetermined income from RH, but it may be better to give up on some of it in order to be closer to hashem. Nowhere does it say that מזונותיו של אדם קצובים לו means I won't earn less that God predetermined and it might be worth it. I thus (personally) have no issue losing 10-20% of my annual income over it but do take it off when I think an objective bystander would think it can have a bigger impact.
Can we agree that as a general rule it is better to wear it than not to wear it?
Assuming we can, then any departure from the general rule is departing from the better course of action, provided of course that there isn't some extenuating circumstance. And therein lies the rub:
Personally, I think extenuating circumstance would be fear of bodily harm, whereas you, and perhaps your rabbonim, view extenuating circumstances as possibly not getting a job. However, I'd submit that even those rabbonim themselves would acknowledge that, all else equal, wearing would be the preferred approach.
I just can't help believe that a person with 100% emunah would ever take off his head covering...
especially to get a job.