Well Ubisoft is far healthier than one or two or even several mega bombs away from being defunct. They are also more heavily invested in PC than consoles for some of their franchises like Siege.
Additionally they experiment far more than other publishers so their chances of not having a mega hit at all for so long that the publisher goes defunct....is not practical. They also do research in game technology that they share and can bank on at any time they want...like they have 4-5 different engine's with extensive documentations allowing a smooth workflow.
I agree that Ubisoft is likely the healthiest storefront apart from steam.
- Blizzard has an uncertain future and even if it was a pc-centric developer, their corporate structure makes it more likely that they could do a 180 on store support in the future if their shareholders think they are not making enough money
- Bethesda is just ramshackles and I have the least faith in them supporting their store just 5 years into the future
- EA is financially healthy, kinda. But they are more prone to AAA bombs and their financial stability comes from mobile and Fifa cards.
- Epic is a company that already abandoned PC gaming once and if they lose the Fortnite money, they will do it again
Remind you, this is not a financial analysis, just my own personal feelings why I don't trust them. I have half a dozen games on Uplay and Origin but I would never start a game catalog there.