Funding a game has always been the risk the suits have to evaluate in the finance dep.
They guesstimate what something will bring and allow the budget according to these estimated finances. That's their job. They will naturally fail quite often. Overfund some stinkers and rake in more money from some unexpected hits. And of course subs can and will change that. But so did crowdfunding, where gamers themselves were asked to take that gamble, in most cases even without the potential of partaking in the profits, which always felt kinda scummy to me, a preorder deluxe model, doing financing without actually invite them to the second half of the job. Kinda like using the passionate dev gamer guy with crunch time and not compensate fairly. The honeymoon phase there is past though. With fans being more reserved and overall the attention less than at first. I guess sub services are also in the decline after the two major services are now established and prices are probably negotiated tougher now when the "frontlines" are established. I guess depending on your game contract it might be a fixed sum or you get a very small amount but for each download, maybe even for played hours, some of the engagement metrics.
I guess if you develop a game, at least AAA, you still have to relie on proper sales and subs and stuff like EGS giveaways should only be seen as bonus money.
So subs as a fundamental part of financing might more be a question for MS internally, and their day one gamble. But Sony has yet to abandon proper sales and any third party can't or shouldn't depend on this for bigger projects. But I guess that's your job as the dev to convince MS that it is worth more if you need more money upfront and want to get it from them instead of other means.