but if I was looking to promote a venue, I would just look to see if anything else on the night I wanted and avoid any possible clash, regardless of the music policy of other venues. I for one wouldn't promote a venue on the same night as an established venue, I would look for another date.
Even oldies venues still need fresher sounds, you just have to look at some of the stuff played at oldies venues, even if it does take 20 years in some cases
The good newer sounds still trickle down to the oldies venues and without the newies venues this wouldn't happen.