Whats the difference between "would have pp" and "simple pas" in this sentence?

What’s the difference between these two sentences?

• The wall would have been blue 10000 years ago.

• The wall was blue 10000 years ago.

• Most scientists would not have put X in the same class as birds in terms of flying ability.

• Most scientists did not put X in the same class as birds in terms of flying ability.

• This would have made flying awkward.

• This made flying awkward.