They are also being potentially pushed in this direction by the HK government, which asked them to support HK's "strategic economic development," which very much includes links to the Gulf right now (especially Saudi, to which there are currently not direct flights). My sense is there's probably not an extra financial incentive to do this, though, just the incentive to avoid awkwardness with the government.

Personally, I'm less interested in this RUH resumption than whatever other routes they open up as a result of this government nudging toward more Southeast Asia and Middle East. I might bet on Cairo someday.