No one from IBM is on the board because Google wants to control the project and apparently has no interest in governing it in conjunction with non-Google entities
> IBM continues to believe that the best way to manage key open source projects such as Istio is with true open governance, under the auspices of a reputable organization with a level playing field for all contributors, transparency for users, and vendor-neutral management of the license and trademarks.
Based on this comment it sounds like IBM is saying that Google's OUC is not a vendor-neutral manager of license and trademark. It's also suggesting that there won't be a level playing field or transparency.
Basically IBM just wants it managed by an independent un-biased entity. Which sounds fair, if the whole purpose of the thing is not profit for one org, but the profit of a community.
More evidence to my argument that it is impossible for a corporation to own and develop a true community-led solution. The corporation is a slave to its shareholders and profit margins, so the community's wishes will never take priority.