Sadly, things haven't progressed very well since then, and the developer has now announced that Second Extinction is ending active development and being permanently delisted - it's already unavailable to buy on the Xbox Store.
The reasoning is the game's lack of success, as well as major issues with leaving early access:
"While Second Extinction is well-loved among our players and the gaming community, it regrettably did not achieve the success we hoped it would. Additionally, some unforeseen show-stopping issues prevented us from leaving Early Access and Game Preview."
"As you may recall, we initially planned to launch the 1.0 version late last year, but the discovery of a few critical issues forced us to pull back close to the release. Unfortunately, it became clear that our small team lacked the resources necessary to hit our quality targets and exit Early Access and Game Preview, and the investment needed to do so was too large for us to bear. After evaluating our options and working during this year to find other potential solutions, this became the reality our team had to face."
If you already own Second Extinction then you'll still be able to enjoy it until sometime next year, but everyone else is sadly out of luck. The good news is that no layoffs are being associated with the game's closure, with team members being moved onto other projects within the Avalanche Studios Group instead.
It's a sad ending for a game that had huge potential, but hopefully the lessons learned from this experience will lead to even greater things in the future. Here's a bit more on what the team is taking away from Second Extinction:
"We’ve come away with a list of things that worked incredibly well, and things we know to avoid for future projects. One thing is for certain – while Second Extinction may be coming to a close, our commitment to crafting memorable moments that capture the magic of gaming will never fade."