Hi,
I think javascript to c# was different because it did not required a total rethinking nor rebuilding of the toolkit and design patterns, with DOTS, it's a complete new system with a completly different approach, the transition is a lot ore demanding and risky.
When DOTS will mature, because, even as is, it is still questionnable wether it's the right approach, some other ECS framework types exists so for Unity own take at ECS to be a successfull one adopted by the industry is still something that remains to be seen. I am sure hutong Games will consider supporting it, there are no reaon why, however Unity learned from these tens years of PlayMaker total dominance in the visual scripting area (litteraly the #1 paid assets of all time on the asset store) and It seems they want to provide a visual scripting environment for DOTS, so the competition between unity/PlayMaker on that aspect will be interesting and certainly a very positive outcome for the developers.
Bye,
Jean