Many games burn out (with their creators) even before half way finished.
The reasons? Many. Be it poor planning, too much spoiler, writers block/too much idea, motivation vanish, or simply life itself.
About this game:
The creator knows that it needs some restructuring and admitted doing it.
This demo gave out a lot of spoiler->the creator has to live up to it.
The creator has a lot of idea so much that it slow down the development work.
The team behind this game works several games in same time.(it slows down but also prevents burn out somewhat)
The mid 2020 Completion date is a good conservative estimate.