OOB for carriers is significantly more complex; especially when you may be the only realistic access option in certain locations. However, given the rise of Starlink I think it becomes closer to "trivial" when the math becomes $100/mo/location + some minimal always-on OOB infrastructure on prem + cloud. Even in heavy-monopoly situations, you can usually guarantee the Starlink to Internet path due to the traffic bypassing the transport carriers on the ground (bent pipe to LEO sat) and landing at IXPs/near telco houses which egress direct to transit carriers.