For the most part, I view the RFP as a way to encourage wrong and ill-fitting service providers or third party consultants to engage with your company or business. Simply put, an RFP is just a tick-a-box approach to seeking skills and services externally. The tick-a-box approach and mentality by it's nature sets up a very black and white context. This is the problem. Business for the most part is not purely objective.
A better approach I think, would to be more proactive and approach only those service providers or companies that are somewhat aligned with your business or company values and vision.
Another solution (for bigger companies) would be to fund smaller independent teams to consult as an acting external supplier.