Depending on the concert. There'll be plenty of events that making free doesn't increase adoption that much because either people aren't interested or because the people who are interested already buy tickets and making it free doesn't tap a wider audience much. Will making COD free on GPU make it 10x more popular? Or do 90% of people who want to play COD already play it?
With a live service game, even one without the implied microtransactions of most LSGs, the risk to putting it on Gamepass must be small, right? If someone pays for a month and then drops out, it's not like they get to keep playing COD. If they want to keep playing, they either have to keep paying, or buy the game. If they are on Playstation, they either have to buy the game, or get Gamepass and stream it to something other than their PS5, or get an Xbox and gamepass. Where is the loss? The only potential loss would be if someone already has GP and plays COD, and that would lead to a loss in growth for Gamepass, but should also prevent some people from leaving the service if they play COD. But I'm doubtful that Xbox, with it's limited install base, has a large enough percentage of COD players to affect the big picture COD market negatively anyway.
Think about it this way, on average recent COD has been selling 20ish million copies. The best selling COD was about 30 million. The worst selling modern era COD was 2016's Infinite Warfare at 13 million. If we assume the the baseline is somewhere around 20 million, and the population is c
onsistent with the trend of 42% Playstation, 26% Xbox, and 28% PC, that would put us at 8.4M Playstation copies, 5.2M Xbox copies, and 5.6M PC copies. Are Steam users going to abandon Steam to play on PC Gamepass? Not according to people using Hellblade 2 steam player counts to infer that the game was a failure. While I'm sure there will be some peel off, I doubt it will be as substantial as the loss to Xbox player numbers. Every full priced purchase at $70 is roughly the same revenue as 4.11 months of Gamepass Ultimate, so if they lost all 5.2M Xbox sales, they would have to sell about 21.4 million months of Gamepass. That's 10.7 million people for 2 months, or 7.13M for 3 months, or 5.35M for 4 months.... all the way down to 1.78M for 12 months. If roughly 1 out of every 3 people who play COD on Xbox don't buy COD on Xbox but play all year on Gamepass, they will have broken even on this move.
More math...
5.2M*$70=364M
Lets imagine a catastrophic situation, where they only sell 3 Million copies on Xbox (3M*$70=210M) and only gain 12 million months of Gamepass (So 1 Million for a whole year, or 2M for 6 months, or 4 million for 3 months, any combination) That would mean they would have lost 2.2M sales on Xbox - More than 40%! And only gained an additional (12 million months * $17) $204M in return, for a total of ($210M+$204M) $414M in revenue. Which is $50M more than the original $364M they got from sales. If they only sell 3 million copies, it would only take just over 9 million months of gamepass to break even. That could work out to 9 million people for one months, or 4.5M people for 2 months, or 3 million parents who put in their debit card once to get little Jimmy to STFU and forget to cancel for 3 months, or maybe a little of all those.
Something else to think about - If the game goes on sale for, say, $50, it would only take 3 months to exceed the same amount of revenue.
Some people will choose to buy a game even if it's on Gamepass and they have Gamepass. Some people will buy DLC for a game on Gamepass, and then buy the game later when the game gets removed. But if someone plays for a few months on Gamepass, and buys a map pack and then cancels Gamepass, they have spent money on a game they do not own, motivating them to buy the game, or re-sub to Gamepass. Plus, if you add people to your user base, the potential to sell them some DLC increases with the size of that player base.
Each copy of Black Ops 6 not sold, but rented, (or sold digitally) is a copy that isn't in the used section at Gamestop. Which means to find a copy of that game next year you will be more likely to have to buy it digitally, or sub to Gamepass again. Microsoft gets $0 from each used copy sold at Gamestop or wherever else.