True believers are at companies because they other motivations than personal wealth. I find most companies have very few true believers.
I am not motivated to work by wealth, and am certainly not going to engage in more than the bare minimum of self-promotion (which has in no way hurt my career).
But the only companies I've worked for where I've been a "true believer" have been the companies I've started.
I am motivated by the work itself and the working conditions.
I don't brag about myself, in large part because I find it so annoying when others do. I am an example of how doing that, at least in the right sorts of companies, is not necessary. Further, it can be actively damaging as it decreases the willingness of others to work with you.