This graph on it's own is alright, but putting a big claim in the title and the top is just jumping to conclusions. Even if fuel inefficiency was a factor, it wasn't the only factor.

All of this data would've been known far before a Concorde ever flew, they were very aware. If it was so blatantly uneconomical, they never would've built them. It wasn't trying to compete with those massive jetliners, it was a plane for the rich and famous. A large amount of passengers isn't necessary when each passenger is playing 2-3x as much for their ticket.

If you actually want to talk about why it was decommissioned, you need to look at a lot more information. How much service they required later on in life, their setbacks from being unable to fly over land due to concerns about the sonic boom, and most importantly the publicized crash of a Concorde. To pin it all on a single statistic is ludicrous.