tl;dr Germans and coordination while mitigating takeover risk (ironically)

StarOffice was a German office suite bought by Sun Microsystems in 1999. Sun open-sourced it in 2000 as OpenOffice.org, which became the major free alternative to Microsoft Office through the 2000s. Sun kept significant control. They owned the trademark, required copyright assignment for contributions, and steered the project's direction. Many community contributors were uneasy with this arrangement but tolerated it because Sun was broadly seen as a good-faith actor.

Oracle acquired Sun in 2010. Oracle had a reputation for being far more aggressive about monetizing and controlling its acquisitions (the Java/Google lawsuit being another example). The OpenOffice.org community had already been frustrated by years of slow decision-making and corporate gatekeeping, and Oracle's arrival made the situation feel untenable.

A group of prominent community members and corporate contributors (including people from Red Hat, Novell/SUSE, Canonical, and Google) announced The Document Foundation in Sep 2010 and forked the codebase as LibreOffice. Oracle eventually donated the OpenOffice.org code to Apache but LibreOffice quickly became the version that mattered.

The reason they had to fork was that a single entity (first Sun, then Oracle) had unchecked power over the project. The Document Foundation was explicitly designed to prevent that. If there's no formal structure, whoever controls the servers, the domain name, the trademark, or the build infrastructure effectively controls the project. A foundation with bylaws, elected leadership, and distributed authority makes it much harder for any single company or individual to take the project hostage.

LibreOffice receives donations, employs some staff, holds trademarks, pays for infrastructure, and sponsors events. Under German law (TDF is registered in Berlin), you need a proper legal entity with accountable governance to do this. You can't just have "some developers" holding a bank account and a trademark informally. The foundation was officially incorporated on February 17, 2012.