Disagree. One could 'think' that, but with no real evidence to support it other than the amount of times a game is pirated, it's really only drawing a conclusion without the bare minimum of necessary facts.
There are reports on it that suggest otherwise. But you're reading too much into my wording. I say "impact" not "big impact" or "small impact". Just "impact".
Because at the end of the day there is an impact on total legitimate sales, but the devs aren't losing out on any real physical revenue.
What they're losing out on is theoretical revenue that may or may not be there.
Of course you have the whole legality issue as well.
But it is very stupid to say that not one person who pirated a game would not have paid for the game if there was no way to pirate.