I don't think they can win over large company, they are just a small nonprofit organization, large companies want to work with other large companies.

Where they can make a difference is for fellow organizations and maybe small companies. A lot of them go to Google because that's the most convenient, even if it sometimes against their principles, they are proposing an alternative.

One minor criticism I have is that while they are not hiding the fact that they are rebranding off-the-shelf free software, they could give them a bit more visibility, should users want to self host at some point.