The gigs I've attended as a guest where high standard highly paid mixed gender bands performed were "across the UK".
If you're with an agency that sounds like they specialise in same gender indie bands then that's not a surprise, you'd need the stats from across all gigs and agencies to know what's most popular, of course if you're a scruffy all male indie band then you're probably already with the right agency and you need another scruffy front man!