I think part of the problem is it is unclear what timescale the prediction they are referring to relates to or which iteration of the proposed network it encompasses. A 9000 passenger a day prediction would seem high for the first 3 months of service (based on current service levels it looks like something like an average of over 50% vehicle occupancy across most of the day, very high & an unlikely prediction for the early loadings), it is more likely to be something intended for further down the line once everything has bedded in. The operators have in fact been very pleased and to some extent surprised by the growth in usage caused by the Busway in Luton and it is certainly doing better than they expected this early in its history. The councillors response seems more of a knee-jerk, back-covering response rather than someone who bothered to actually check what the question was referring to before responding and in so doing giving an answer that looks somewhat silly and as if he is trying to hide something when he probably isn't. There has been a reduction in the frequency between Luton & Dunstable (though not by as much as the Busway has added) & the B, C & E all effectively have replaced & improved upon existing services - the B & C have replaced town services in Dunstable whilst extending them to Luton Station which wouldn't have been cost effective without the Busway whilst the E has enabled a doubling of the frequency to Toddington with no extra resource, all of these helping to produce extra growth that would not have been possible without the Busway (the Arriva A is more of an additional service and offers a different sort of extra offering to the other services on the Busway)
That said it also depends on what service plan the predictions refer to as earlier service plans had a much wider network of services extending beyond Dunstable than is currently provided and the fact that they haven't materialised is, to some extent, due to the recession as the costs (& risks) of introducing the much wider network was too much for the operators to do in one big bang in uncertain times (particularly given the nature of the vehicle requirements to run on a Busway, ignoring relative ages it is size & ability to take guidewheels which are the limiting factor & as a consequence produce higher operating costs than would otherwise exist - the B & C have effectively gone from minibuses to heavyweight Scanias & the E from assorted Darts to the same). Whether the 9000 per day can be achieved in the future, whether it needs these extra services to do it & whether the operators feel comfortable in the future in introducing them remains to be seen and could affect whether it is seen as a success which will be unfair to the success it has achieved on the corridors it is covering. It is probable that the council did overegg the pudding in trying to build a business case, not in the growth that could be achieved to each route but in the number & range of services they could attract to the Busway from the off.