Microsoft!
Please consider that you have many big loyal customer in industries where legal compliance standards prevent them to use the cloud. As example defence, energy, government etc in countries where you not have sovereign gov cloud (Sweden). They either use a M365 Hybrid or a pure SharePoint OnPrem to store NSI classified data.
Without OOS these solution will be really old school.
If I was the head of M365 products I would see M365 Hybrid solutions and SharePoint OnPrem as a strategic competitive advantage against competitive solutions. Without them you will loose a lot of customers.
OOS is definitely an important component i above. Without the OnPrem solutions is nothing more than an old ECM or fileservers.
Best Reg Magnus Ericsson from Xenit Sweden.