Wikipedia is usually pretty good at giving an overview of the situation.
> In September 2010, the majority of outside OpenOffice.org developers left the project, due to concerns over Sun and then Oracle's management of the project
> […]
> In April 2011, Oracle stopped development of OpenOffice.org
— https://en.wikipedia.org/wiki/OpenOffice.org#History
But the OpenOffice brand was already built, so obviously a lot of people still think it is the most active project.
Presumably, Oracle did not know what to do with this asset they bought, but they thought they might be able to squeeze value out of it. They believed the only way to do so was to have total control over it, which removed all value from it (except for the brand). Then they put it in an Apache-shaped trash, along with the brand.