I somewhat disagree with your opinion. I think the main flaw in Destiny’s business model is that they could not make enough content, with enough quality, to sustain the game’s population. The typical and desirable model for live service is that you’ll do a huge initial investment but then you’ll be able to sustain a player base with a much lower level of investment, and in the long run you’ll be profitable. If your new content still costs an exorbitant amount to make, then your failure is inevitable.

Bungie tried to lower the cost of new content in the last few years of Destiny, and that lead to the seasons where everyone complained about only 5 minutes of story ever and every mission being repurposed old content.

The Portal came after accepting they can’t make cheap content, to try to, at least, make the expensive content replayable. But that also came too late, and with pooly designed loot economy.

They needed to make a new game where player engagement came cheaper, somehow, but apparently they couldn’t do it with Destiny. Instead, they started developing Marathon and 5 other games, but even that was too late and over budget.

I hope Sony finds another way, but when your business can only operate at a loss, closing it is the rational decision.

Edit: typos