Upthread and elsewhere
@Urban Sky raised the utility of bus-train connections, passenger expectations about buses holding for delayed trains and vice versa. At the moment VIA connections with bus operators are, as I understand it, a convenience marketing arrangement but the Amtrak Thruway system gives a glimpse of what an extensive and more formalized arrangement could look like but with the continuance of the bus operator's own corporate and branding identity, since they would use the same drivers and vehicles for other routes.
It is accepted that, like direct provincial support of rail service existing and expanded, there would likely need to be some changes in thinking in Ottawa, if not legislative underpinning, to see a move towards this model. Given the battering the private bus sector has taken nationwide in the last 36 months or so, there might be some appetite for cooperation rather than competition.
The one thing that such arrangements have going for them in the 2020s is the expansion of trainset tracking and motorcoach tracking. This allows dispatchers on both sides of the arrangements to estimate the degree of impact to the service and in turn alert passengers with firm bookings, without relying on the other operator to provide initial notification of the issue.
*edit to correct link to Urban Sky to the right username