I've heard this said elsewhere and I'm not entirely sure of the logic of this statement, to be honest with you. This is something they actually mentioned when they launched the Vita, so it's patently not just a reaction to the Vita's sales (in fact a similar scheme was also talked about when the PS3 launched, but with PSP games rather than Vita obviously). Given the 'extra' copies will almost certainly be digital rather than being 'hard' copies, the cost of doing it per unit is close to nil, since the digital version will have to be made anyway to allow for actual digital sales.
Initially, you would assume they will be losing sales but I'm not so sure that's going to happen.
Say you're planning to buy, I dunno, that Ratchet & Clank game. Were you planning to buy it for your Vita
and your PS3? Almost certainly not. You were more than likely planning to buy it for one or the other. So you were 'one unit sale'. If they offer them in a pack together, you're still 'one unit sale'. This will be true for the vast majority of PS3 or Vita owners. So they're effectively a zero sum (given the purchase cost of the two versions is likely to be roughly in proportion to their production cost).
OK, so you will have a small minority of users who
were planning to buy it for both. So they are
lost sales.
But what you have as well is a bunch of 'floating voters' who were undecided as to whether to buy the game or not. The package you've got now represents higher value (say not double, say 50% extra) than the 'single format package' item you would otherwise have been selling. Some of those floating voters are going to look at it and say 'actually, that represents a bit of a bargain, I am going to buy that game after all'. Those are
gained sales.
Now, I don't know which is actually the greater of groups 2 and 3. Personally, my opinion is the number of people who buy the same game at the same time on two platforms they owned both of would be vanishingly small, especially for games that aren't in the 'massive blockbuster' category. And therefore this tactic may actually increase total revenue, even if at first glance it might appear to be giving away something you could otherwise charge for.
Remember, supermarkets actually do the same thing all the time and few of them are struggling financially, even though the free stuff they give away actually has a finite production cost per unit they still have to pay.
This does hinge on Ernie's point of them being able to lock the 'extra copy' to the buyer of the 'original copy'. If the buyer can actually give that extra copy away, then you're eating into the numbers in group 1 and therefore you
are losing sales.