Re: "not winning a contract surely hurts, but it's not a loss"
"not winning a bid IS a loss"
OK. Based on the description you just gave, I see a real loss and it is (at most) the cost of the up front pre-sales work. Life's often like that when up front pre-sales work is involved. Others might call it cost of doing business.
The loss is surely not the cost of the business that you bid for but didn't win? What kind of accounting policy would allow that as a tax deductible loss?
Now, what was the original topic here? Internet ad-flinging. Where's the real loss in that picture? E.g. where's the equivalent of the up front pre-sales work?