Whilst that is a fact. Other factors have to be considered, It's on a week night, possible work/school commitments, racing elsewhere.
This is a chance for these riders to get track time & for the most part it's the same group of riders each week. I can remember when we had second half racing with 3 man teams followed by scratch races all of which were viewed by only a couple of spectators but for those guys out on track it could have been the world final. For many it will be the highest level they achieve some may progress through the leagues & maybe an international star. Everyone has to start somewhere & if Birmingham in their last season can give a starting point to a Champion they should be applauded.