TLOU2 actually sold 10 million units and that 4 million copies were actually sold in the release weekend. We know they weren't actually lying about that figure because the Insomniac leak showed that they sold 10.3 million units. The problem is that it took like 2 years after launch to reach that number and the net sales were really low for that number ($447 million), indicating that the game was enormously discounted. Seeing as how 4 million copies were sold in the first weekend at full $60 price, that's going to be around $240 million out of that $447 million. Leaving ~$207 million in sales across 6.3 million copies comes out to about $32.85 per copy for that 6.3 million copies ($43.39 per copy across all 10.3 million copies).
For comparison:
-Miles Morales ($40 glorified DLC turned full game) sold 11.1 million sell-in and $427 million in net sales. That comes out to $38.46 per copy, hardly much of a drop when the game released at $40.
-Ghost of Tsushima had 7.6 million sell-in for $397 million in net sales. That comes out to $52.23 per copy, a very minimal drop compared to its $60 launch price. The leak also showed that the remaster sold 1.8 million sell-in for $107 million in net sales ($59.44 per copy).
Keep in mind, the FTC trial revealed that TLOU2 cost $220 million in development costs while Ghost of Tsushima cost only $60 million. We also learned that Miles Morales cost $156 million to make. If we're looking at just raw dev costs versus net sales:
-TLOU2 was up $227 million
-Miles Morales was up $271 million
-Ghost of Tsushima was up $337 million
This is ignoring marketing costs and considering how heavily TLOU2 was advertised, there's a possibility it had a movie budget in advertising somewhere between $80 million to $200 million.