Yeah, I am reading that as: those studios, in the future.But he also says 'are excited to bring UE5 features to life.'
I mean, I'm also not sure why Epic would say those things about it not being available until 2021 if they weren't true, including:
Unreal Engine 5 will be available in preview in early 2021, and in full release late in 2021, supporting next-generation consoles, current-generation consoles, PC, Mac, iOS, and Android.
They do go on to say:
We’re designing for forward compatibility, so you can get started with next-gen development now in UE4 and move your projects to UE5 when ready.
We will release Fortnite, built with UE4, on next-gen consoles at launch and, in keeping with our commitment to prove out industry-leading features through internal production, migrate the game to UE5 in mid-2021.
This last part is interesting because it means you can re-release a finished UE4 game in UE5.