This is great, we are talking about sports memorabilia here, an autographed ball correct? The sheer existence of mankind I don't believe is hanging in the balance.
Did we forget we still operate in a free market economy with supply and demand pretty much setting the tone. If I want to sell something for a certain price and I am not getting any interest that pretty much speaks for itself. If I am wanting to get a deal and make an offer in that direction, and I am not getting any takers it speaks for itself.
I can't be upset either way.
We can't force somebody to buy/sell something at the price we think it should be done at.
What ever happened to the Stephen Covey win/win mentality?
As a "seller" I have had someone make me an offer and basically said I was trash if I didn't take it. The added commentary at the end of their offer told me I wasn't going to deal with them regardless and I just laughed it off.
I have also had someone make me an offer which I didn't take and they simply said to get in touch if I ever decide to sell in their range. Which I can appreciate because as a collector, I usually have a range I try to stay in, while trying to get the best deal.
More win/win or agree to disagree and move on

, Less my way or the highway