That's a ridiculous statement. Virgin have a contract to run the West Coast Intercity network that connects London with cities up the west side of the UK. They don't have the contract for the East Coast or the networks heading East or West from London including Eurostar which carries more people than airplanes from London to Paris.
Virgin has 1 out of 7 Intercity franchises, and none of the 18 regional franchises. And its one Intercity franchise is currently in limbo - Virgin lost it, but has appealed the decision. They've gotten a temporary extension on their contract while the franchise selection process is reviewed.
Most of the other operators have multiple franchises, either directly or through subsidiaries - Virgin is a quite small player.
As much as I love the Virgin trains in the UK, a substantial part of it is not covered. I travelled down from Scotland through Wales and over into London and only a portion was covered by Virgin (sadly).