Some RFPs are definitely rigged. Spotting them is part of being a good consultant. See upthread for a deeper discussion on this.
"Most" RFPs are not rigged.
A company that submits 153 RFP responses and wins only 3 has a problem, and it isn't with the concept of RFPs. Perhaps their pricing is wildly out of whack. For awhile, there were things we did wrong with our proposals that cost us several RFPs. We figured them out, resolved them, and systematically improved our win rate.
There is no way that 1.9% (or even 5%) of RFPs are bogus.