This was explained by Shekhar Gupta in an opinion in the Print, can't find it now however main grouse :
1) Punjab has fallen in its stature in India, with practically no industry worth mentioning operating in the State. 
2) The Punjabi diaspora too is lagging behind other Indian groups that have migrated to the West in terms of median incomes. 

My first impression when I read it was " Absolutely Childish" if true. 

Khalistan movement destroyed Punjab. It is they who chased out Hindu business families like Mittal's, Munjals. Else the Hero Motorcycle group had planned to set up their manufacturing in Ludhiana where they manufactured bicycles for decades. Khalistani's chased them out and they established their facility in Haryana and today they are largest manufacturer of two wheelers in the world.