It's difficult for me to see how funk can't have influenced breakbeats.
Because funk is like the
opposite of breakbeak. Funk percussion is a regular, rhythmic beat, and then in the middle of the song there's a couple measures of the "break", where the percussionist goes off-rhythm to solo.
Breakbeats is what you get if you take just that period of the break and make a whole song out of it. It's like making music out of the negative space that surrounds a funk song.
I'm not saying that there's no relationship, obviously there is. But breakbeats aren't the natural evolution of funk, the way funk evolved from other genres; they're a quantum leap across the musical space.
Without recent precedent, in my view. It's fine if you disagree. Although the thing you mentioned, about electronic amplification of vibrating strings, that was pretty significant, too. And I think we're on the cusp of a similar development, where digital instruments and games like Guitar Hero will usher in an age where people make music on instruments that are designed for easy human use, not forced into certain configurations by the necessities of generating musical sound with physical materials.