Firefox OS at least lives on as KaiOS, more successful market-wise than Mozilla ever was with it.
Fairphone barely (it seems) keeps surviving and might still count somewhat as an "alternative" phone, even if their primary platform is Android.
A new OS is a big task to get to market - non-open contenders have failed too. The combination of an more open phone (which likely comes with compromises) and a new OS just makes the task even harder, and while enthusiastic, I'm not sure the market of people who'd prefer that product is large enough to make it real, sadly.
Fairphone barely (it seems) keeps surviving and might still count somewhat as an "alternative" phone, even if their primary platform is Android.
A new OS is a big task to get to market - non-open contenders have failed too. The combination of an more open phone (which likely comes with compromises) and a new OS just makes the task even harder, and while enthusiastic, I'm not sure the market of people who'd prefer that product is large enough to make it real, sadly.