Aberdare and Merthyr haven't been among the stronger rugby areas traditionally. The Rhondda has generally had bigger football than rugby teams. The valleys were hit massively in the 1920s and that put an end to the possibility of having valleys sides in the football league. It's difficult to make a case for either club surviving and thriving - they were perennial strugglers in the football league. What if they had survived? I think it would have had an impact in those areas and Wales might have enjoyed a little more success on the international stage