Developing an in-house OS is fine as a bargaining chip during Android contract negotiations, but a new OS with no apps won’t resonate with customers when Android is available from every other OEM. Tizen hasn’t been able to compete with Android on smartphones, but Samsung has used it almost exclusively on smartphones and other “smart” electronics that don’t have much of an established app ecosystem.
How good of a bargaining chip could this be if it didn’t work for Windows OEMs back in the 90’s and Samsung recently. Google knows this. Not sure why Huawei doesn’t yet.