Why did Esri choose to create zLas, a proprietary format, rather than collaborating with or building on existing open standards like LASzip?

[TomMacWright1]

For background, see Paul Ramsey's article: Format Wars Episode V: LIDAR - Boundless‌

And James Fee: LAS, LAZ, LasZip, zLAS and You‌

How does this decision square with Esri's "Open" initiative?