Having built one of the the first charitable crowdfunding websites in the world, I feel uniquely qualified to answer this. The answer is that in the non-profit sector (and I'd argue enterprise as well), it's not one or the other, it's really both. Without a "forcing function" of some bottom-up adoption, it's really difficult to get non-profit decision makers' attention. But without the ability to answer a lot of questions, and hand-hold them to adoption, no bottom-up approach is going to really gain traction.
Happy to talk to you in a call about your specific questions and challenges.