I'm genuinely curious what they donate, maybe it's already that much? More? Less? No idea. Also, at their scale cost of FTEs dedicated to upstream open source becomes a significant consideration. How many kernel hackers do they employ?
Every engineer worth retaining is realistically responsible for at least $2000 more in real corporate income or institutional savings than was anticipated in any single year. The bigger the organization the more I would think they leverage the same engineering successes to higher dollar amounts than that.
Many of course get bonuses well in excess of this baseline when even larger contributions are recognized.
I would like to see someone prosperous & generous donate to the Syslinux Project so they can update to a point where they have a Microsoft-signed SecureBoot universal multiboot solution for UEFI so it will be as useful as it was under BIOS booting. Ideally, if a signed "shim" is involved it would be universal so it would boot any form of Linux using either GRUB or Syslinux, once the official update is released and adopted by the distros.