Even small-scale stuff that nobody writes articles about like putting a personal guarantee on a 2-year commercial office lease or a line of credit qualifies as sacrifice and is actually quite risky.

I'd offer a small edit on the premise and say that it isn't necessarily a willingness to be poor, but a willingness to go broke for your convictions that is important. Being poor/impoverished is a mindset, being broke is a temporary condition.

Somewhat tangentially related is the derivatives trader mindset which I have been reading about recently.