Blonde said:
'Tis the way they are marketed I think - well, AUK doesn't really market their rides enough, that's the problem! I notice hardly any are mentioned in C Plus or other mags in the 'what's on' bit, it's mostly sportives. They should advertise the shorter, more accessible distance events (eg. 50-150km) in more places IMO - they are the ones that attract more people so the number of entries should pay for any advertising costs. The image of audax according to the people I know who are not members of AUK, is not very attractive. I'm not sure why this is, exactly, but AUK needs to find out, do some research and do something about it.
The way I understand it is in terms of "value adding"
Both Sportifs and Audaxes are rides up the road. Now, if the Sporif can give you a timing chip, free stuff on the course (ie gels), massage at the end and a signposted course then that is "adding value" to the event.
Because they do this they attract more people. The cost is not entirely irrelevant but when you consider that most people value their weekends and have already spent 500 quid+ on a bike then 5 quid for an audax or 15 for a sportif it isn't going to be a major deciding point.
So more people are likely to choose sportifs as they see them as a more value packed way to spend their special weekend.
The higher costs incurred by the Sportif people mean they can advertise as a fractional part of their overheads, whereas for audax this is not an option: there is no budget for it.
Lest we just say "well that's the end of audax" remember that some of the Sportif organisers are commercial and are trying to make a profit. That's an additional cost that audaxes don't have. Like Gavin says, all the audax organisers have to do is budget a tiny amount for basic publicity.