"Yeah, that first reaction," mused Bisson in a Eurogamer interview. "You know, I did the same thing - why do a multiplayer Tomb Raider? We don't have to have multiplayer to have a successful single-player. I do agree on that. I do agree that it's not critical to do that."
The reasons for its existence, then, are twofold.
“The first is a selfish reason of mine,” explained Bisson. “With single player, there's a start and there's an end. And you have some games with a rich universe, and you think you want to stay there forever and then it ends.
"You want to stay in that universe - there are some games like that. One of things that was pitched was can we make that Tomb Raider universe persistent? We wanted to do that, and we explored new maps and new types of gameplay, and for me that's very meaningful - taking that world and making it persistent.”
The second reason is that Crystal Dynamics’ isometric co-op Lara spin-off was really rather good.
“I think they had some success with Guardian of Light, but when they were doing it people were asking why they were doing it. They stuck to their guns and they ended up with something pretty successful, and that was pretty good, and Darryl [Gallagher, Crystal Dynamics' head] came in and said he wanted to push that, he wanted to create that core experience and have it also a competitive experience."
Eidos Montreal's Tomb Raider team, meanwhile, isn't built from Human Revolution veterans better put to work on Thief 4 - it's mainly made up of new recruits, some of whom have variously worked on Gears of War, Far Cry and Red Dead Redemption.
So there we have it. Are you convinced yet? I suppose the proof will be in the thistles-and-spike-trap pudding.