Indeed, that's one of the biggest losses of the Chart Show repeats being taken off. That would have been even more so if they were showing the Channel 4 editions, as the show was less commercial on there, and played stuff that wouldn't have got much (if any) airplay anywhere else at the time- let alone now.
One thing though is at the moment I'm making some copies of the episodes The Vault has shown so far. In fact, the amount of people I've made copies for since the run began back in December has been quite high, most of which are because they don't have access to The Vault themselves. There is certianly an audience out there for these repeats, but there's plenty of people who either wanted to see it but don't have access to The Vault or quite simply weren't aware of the repeats in the first place.
I hope they do try again at some point in the future, with a better timeslot and more promotion. The new Freesat service is launching next year, which will increase the potential audience. Wait for the amount of Freesat viewers to build up, and a reasonable promotion campaign across all of the channels could well work wonders.