I tend to think of signs as being evidence of intensity of support, not necessarily breadth of support. More signs means people who are really excited about their candidate, but not necessarily more people supporting that candidate.
That being said, I still think Trump is winning right now. IIRC, the last Ohio poll had him up by 3%, and I can’t see any reason to think that’s not legitimate.
I definitely agree with you on that. Yard signs aren’t a scientific polling of balanced demographics. The one caveat I’d throw in there is that I went through the richest neighborhoods (Indian Hills, Cincinnati), and the poorest (Adams County). The absence of Clinton signs is striking.
If there’s no intensity at all across a range of neighborhoods for Clinton, then that doesn’t speak well for the vigor of her supporters. Maybe they’re all out having coughing fits.