What's giving you pause? According to the link, Express is undergoing extensive and active development...
Apparently IBM threw a few guys into discovery on the project a few weeks ago and they may actively get involved, but it is yet to be seen. Maybe IBM just wants to own it and doesn't care what happens to the project one way or the next. I have no way of knowing what IBM's intentions are, and I think that's the concern of the maintainer, dougwilson.
"I continue to work in community-owned organizations on GitHub, and if Express were to ever join a community org like "expressjs", I may be back."
Yikes.