$$$, what else? Honest people that want to investigate the world, even with the bias of the desire to find evidence of deities, etc., won't outright fabricate results. After all, if your desire is to learn and spread that knowledge, knowingly making stuff up is completely counter to that desire.
Money may play a role in some cases, but I suspect it's far more primal than that. It's about self-preservation, even existential. There's an onion-like layering going on of theology, philosophy, values, and paradigm going on; for a person it can feel a bit like a Jenga tower, where all the pieces need to fit just right and if one piece is removed the entire tower is made unstable. And that's a tower that represents one's own self identity. For many it is a matter of one's own salvation that is at stake. Notice how often Creationists treat a literal interpretation of Genesis as something so foundational that to take that away means the entire Christian doctrine of redemption, the story of Jesus itself, is irreparably lost if it is taken away. Not all Christians are like that obviously, but for some that is precisely the sort of existential crisis that they are facing--if just one cherished idea is falsified,
then the entirety is falsified (in their own mind).
I often end up addressing theology and biblical hermeneutics on this board with fellow Christians who are Creationists, and that's not because I've forgotten that this is a science board and not a theology board; it's because the heart of the issue isn't really about science at all, the heart of the issue really is theological. In my own life experience my transition from being a YEC (I was raised with Young Earth Creationism, that was my own world view, and it was essential to my own self-identity as a Christian up and into my early 20's) to not being a YEC had very little to do with science. I grew up watching a lot of scientific programming, reading books, and so I had a fairly basic grasp of evolution in concept--but that didn't matter because of the hard-wired theological, existential, issues involved. What provided me with the transition (which was hardly immediate, it was something that happened slowly over a couple years) was a changing in theology. It was a fundamental paradigmatic shift, from seeing my own salvation as about me better getting all my t's crossed and i's dotted OR ELSE, to seeing my salvation through the graciousness of Jesus who freely gives Himself to the world in love. This may not mean a whole lot to someone who isn't religious, but from a religious perspective this can be a radical change in how one's entire religious outlook is turned on its head.
The take away from this, is that for many this really is a deep, primal, existential issue. Again, money may play a role for some, but I suspect that money plays less a role than one might think--it's about self preservation.
-CryptoLutheran