On GP, I don't think the service will close or fail, but it might suffer what I call the "PS+ effect".
PS+ was an excellent service on PS3: you got multiple games, often AAA, and less than a year old! It was still optional, however.
On PS4, PS+ became a requirement, yet the quality of the service did not quite stack up: games became more often indies, and bigger titles were less frequent and much older. While quality is subjective, the reduction in prestige was evident.
So what happened? Now, capitalism want capital, but there's more here than just "Sony greedy" here.
At the end of PS3, publishers weren't seeing much returns: the digital marketplace was smaller, and the end of a gen very competitive with over 7 years of titles to compete for a player's attention.
The service being optional, it meant publishers could sacrifice a month's sales for potentially higher DLC sales and some exposure, without risking much long-term profit. This meant Sony could get better deals on bigger games.
The start of the PS4 gen proved much different: online profits kept growing, and fewer titles had to compete for a player's attention given fewer next-gen exclusives were available. A much bigger audience, due to PS+ being required for online now, meant publishers ultimately would ask for more money, and fewer bigger games became available.
This improved over the gen, but big games still take longer to get on PS+ than they used to, and there's fewer games per month overall.
Ultimately a bigger audience, less competition and higher digital adoption meant bigger games were harder to get.
Similarly, as GP grows, it becomes less profitable for publishers to put their games there, especially if players shift back from PS to XBox. DmC5 for example sold over 4 times as much on PS4, meaning MS could get a much better deal on it for GP than Sony could for PSNow, even discounting MS's much more aggressive spending.
Moving into next-gen, high-spending players migrating to next-gen will have fewer next-gen games competing for their attention, and MS might have to rely more heavily on their own first-party for GP, which could explain their unwillingness to release any next-gen exclusives.