My last round of warm intro (thanks sam) VC partner talks had 100% failure rate too. There's no pattern you can draw here. I had great talks with some two-partner firms. Other two-partner firms did the whole "yes, but only if you're more successful in another 18 months." I did get one absolute "not this time, but stay in touch" decline that was exceedingly professional. SV Angel was the nicest in that they further warm-intro'd me to another 3-5 people. The worst contact was a16z actually. Go figure?