Is there any sort of common cause for the repeated failure of cross-border passenger rail travel, as described here?

Is the traffic (not assuming future increases thanks to good service, something that may or may not materialize) simply insufficient to run these lines profitably?

Is the interference with freight lines so severe that the companies would just prefer to cut them?

Is it just laziness on the part of the relevant companies, who don't have the managerial energy to keep things running properly?

Were these lines dependent upon state subsidy that has since evaporated?

Have new barriers to inter-state operation developed?

Or is every case just unique, and an odd confluence of service cancellations just happened to fall at the same time?