One way I think it might be different is that with traditional sales, the metric for success is very clear. How much did the game sell? With GP, the metric for success is whether it drives GP subscription numbers. With all the different irons in the fire at the same time, that can be difficult to quantify -- unless it's a huge, long-anticipated game like Starfield, surrounded by a desert of other releases. Then you can see GP sub numbers bounce up very noticeably, even console purchases.
But think about smaller titles, less noticeable ones. From a traditional sales perspective, it's very easy to know whether they have been successful: How much did they sell, relative to their budget? But in judging a game based on increases in GP subscriptions, a smaller game might not make any discernable impact at all. So how do they know if it's been successful? Amount of time played? If that doesn't add to their sub numbers, is that a success? It becomes more ambiguous.