PSL need more time to get popular and if you make  comparison with IPL then they have to go a long way to match that level. After big bash league IPL has been the most popular cricket league and worldwide cricket fans eagerly wait to enjoy this league. Its just not only like that IPL got strong support from BCCI but also indian bollywood community gave tremendous support which bring massive popularity in a short time. I haven't seen this type of celebrity and business tycoons involvement in other cricket leagues. Even their football leagues are also getting popular day by day and have same support source.     

Due to Pakistan's terrorist attack on Srilanka cricket team ICC put restrictions on hosting cricket matches and it was a really bad time for PCB. After this few years later with the support of Pakistan government Pakistan cricket board managed to run cricket matches again and as a result PSL launched. So in a situation like this its need more time and hopefully they will be able to get best players on their league in upcoming seasons.