Of course, they just need to inject the right content into it and it'll be fine. Counter-Strike Global Offensive was a dead game with barely over 20,000 concurrent players for its first 18 months, after the Arms Deal update it became one of the biggest FPS games ever.
CS GO also came out way back in 2012. Back then, the market for live-service GaaS shooters was practically non-existent. It was also WAY less crowded and competitive.
Today's market is vastly different; Overwatch 2 (soon), VALORANT, Apex Legends, COD Warzone, Fortnite, CS GO, Destiny 2, etc. are all either very active and thriving live-service shooters, or will be in the case of Overwatch 2 when it launches, not slowing down or stopping their own growth momentum which means they'll just keep increasing the gap between them and Halo Infinite. HI has to do something so innovative and plentiful with new content that it actually blows those games out of the water in order to gain back some serious numbers in terms of playerbase and revenue.
Realistically speaking, that will never happen. 343i simply don't have the chops for it, whether that's down to upper management or creative staff doesn't necessarily matter anymore. Just adding in campaign co-op and Forge won't be enough in light of what the competition is doing. Even a Battle Royale in itself won't be enough, regardless what spin on the formula they have. HI would actually need to innovate big-time with something new that the other games have to quickly try adding themselves, and 343i doesn't have the vision or drive to be leaders in that respect.
So I guess to answer the OP of the thread: I think Halo Infinite will "survive" as in just have a small but dedicated hardcore community; the average community size (in terms of concurrent players) on Steam seems to be stablizing around 4,500 - 5,000 players. It's probably around 60,000 - 70,000 on Xbox, and probably won't drop too much lower. New seasons with stuff like campaign co-op and Forge will give it some bumps, along with new maps, but those new numbers won't sustain and they'll quickly drop off again. Anything that might give some decent bump in overall numbers will be the Battle Royale mode, but that depends on how good it actually is and, again, what new map/guns/skins content come along with it.
To say Halo Infinite's been a failure in reinvigorating the IP is an understatement.