You are correct that it is usually not worth the effort unless you already have established relationship with that client and you are talking about $100,000 or more per year. We sell B2B SAAS and a few times, I was daring enough to try crazy RFPs only to find out that they anyway went their existing preferred vendor and RFP was just a checklist they had to do for compliance needs. A lot of companies float RFP because they have to in order to select a vendor and in many cases, vendors are already decided internally (usually existing vendor) and is just a formality/paper work/checkbox. Not to mention crazy requirements. One RFP needed everything on paper (yes paper) and we literally printed 100 pages and had to mail it physically. :) Then it was radio silence. I literally got someone in our team to call a point of contact (we were not supposed to) and ask for status after a few weeks and all we got was "we went with existing vendor. sorry". That was the last RFP we did until now.