Possibly a reaction to Valve and Discord's recent announcement of similar (more fully featured) releases. But I may well be wrong, and this was planned for a while, with a sturdy roadmap and a MVP release.
Or it's a late-ish reaction to the drama[0] surrounding Unity's "sudden" blocking of Improbable's SpatialOS cloud platform (if you believe Improbable - Unity said they were warned months in advance, Improbable said it was without warning). Then, within a couple days, Unity made an announcement[1] for their own paid cloud gaming plugin. It was all over HackerNews[2] in January when it happened with lots of commenters quipping that it's time to move to Unreal or GoDot Engine. During these days of back-and-forth drama between Improbable and Unity, Tim Sweeney from Unreal Games jumped into the fray and was tweeting his constant disapproval (and further muddying the waters with inaccurate information), at the end of which "Epic Games and Improbable announced the establishment of a US $25m fund to help concerned Unity customers shift their games over to Epic's Unreal Engine."
I'm still waiting to hear how they plan to fund devs but after following Tim Sweeney's recent behavior (i.e. the tweets above, plus paying Coffee Stain Studios to move their upcoming and popular (at least on Reddit) game "Satisfactory" off of Steam and do an exclusivity deal with Epic Games Store, which has caused nothing but bad press on Reddit), I would expect this fund will be nothing more than vouchers to use the paid-version of Unreal Engine for a limited time period, after which you will hopefully be reliant and forced to continue payment. Only time will tell I suppose. And competition is always a good thing.
Why even bother making an announcement?
I'm still waiting to hear how they plan to fund devs but after following Tim Sweeney's recent behavior (i.e. the tweets above, plus paying Coffee Stain Studios to move their upcoming and popular (at least on Reddit) game "Satisfactory" off of Steam and do an exclusivity deal with Epic Games Store, which has caused nothing but bad press on Reddit), I would expect this fund will be nothing more than vouchers to use the paid-version of Unreal Engine for a limited time period, after which you will hopefully be reliant and forced to continue payment. Only time will tell I suppose. And competition is always a good thing.
[0]: https://www.oneangrygamer.net/2019/01/unity-announces-cloud-...
[1]: https://unity.com/solutions/real-time-multiplayer/game-serve...
[2]: https://news.ycombinator.com/item?id=18874400