I don’t foresee this happening even if a service does return. Mears and Disney have always had what was really a mutually beneficial relationship. Following the DME termination, Mears was actually able to raise some of their rates in other, more lucrative areas while maintaining exclusivity.
Additionally, Disney has never operated any sort of mass transportation outside of their own property (with the exception of Minnie vans which are lower risk than motorcoaches). Disney won’t even operate their own CP shuttles for liability reasons. It’s simply worth the money to shift the risk to a third party.