There is still rail-bus service from Lillooet south to Shalalth (Seaton Portage), though it's not exactly scheduled and sort of first-come first-served with preference given to the locals (natives). You have to show up at the right place/right time to get a ride, and be prepared to stay a while (potentially) at your destination. AFAIK they don't go all the way south to D'Arcy. Very pretty country... unbelievably rugged... but nevertheless a fair amount of infrastructure (the railway, hydro projects, etc.) which all cost a fortune to construct. Just not very many people.

CN bought (leased, stole) BC Rail mostly for the traffic base. Formerly most of those wood products were hauled south over the old PGE from wherever to North Vancouver, then interchanged with the ROTW from there. CN extracts roughly the same amount of stuff but is able to route it into their system for destinations south/east more easily, rather than having to take it all the way from North Van to... wherever. The line from roughly Prince George south was essentially just a (very expensive) through-route with little on-line traffic. From CN's perspective, the acquisition of BC Rail was simply cutting out the middle-man.