Don't count on that just yet. ABC has a longer history in Television than Fox, so the ABC name will likely stick around in some form. In fact ABC as a name has to stick around due to FCC licensing of the broadcast channels, they can't change those to Fox.
What will likely happen is ABC studios will continue to produce shows for the broadcast channels. And 20th Century Fox Television will focus on cable. With both contributing to streaming.
This makes the most sense since Fox TV channels (stayed with New Fox) will lose all its 20th Century Fox Television content in 2021 or 2022.
They'll probably just merge 20th Century Fox TV and ABC but keep the ABC name.