You need some reality check, there is no punjabism in punjab due to serious caste differences, a jatt does not see an arain as a kin, a gujjar does not see a rajput as his kin despite speaking the same language. Go visit some villages in the heartland of punjab such as gujranwala or gujrat. People living in punjab (call them punjabi due to linguistic reasons) have their own caste based organizations and even hospitals and other charities. There is jatt ittehad, arain association, or rajput ittehad and so on. All of them exist all over punjab but you will never find a punjabi ittehad or something like that.
The point is very simple punjabis of different castes don't feel connected to each other on racial basis but rather only on linguistic and geographical basis. And it is wrong to presume that punjabis of different castes intermarry , this is not true for any area outside perhaps lahore or some other big cities, all castes in punjab marry only within their own caste due to racial sensitivities. Every new group that arrives in punjab becomes a new caste and follow the rules of the punjabi society, all the tribes such as arain, jatt, gujjars and rajputs have mostly come out of punjab from areas and settled in various parts of punjab within the last thousand years or in some rare cases within the last two thousand years. Kashmiri , pathan and balochs living in punjab are as much punjabi as any jatt, gujjar, arain or rajput because all of them are migrants from other areas , the difference is only of time scale, however all these groups were always living in geographically closer areas to punjab and hence there were significant cultural and liguistic overlaps between them which helped them assimilate in the existing populations of punjab.
Contrary to popular view most of the paksitani punjab was historically a forested area and only few settlements were there in the last thousand years. The major population booms in this part of punjab (west punjab) occured during mughaly (just 400 years ago) and particularly later during british time (150 years ago) when most of the numerous clans within tribes like jatts, gujjars, arain and gujjars were settled in newly created agricultural colonies. Some of them came from east punjab (which was more anciently populated) , sindh, rajashtan and indian gujarat province all of which are geographically very close to pakistani punjab. This is the main reason why a jatt does not feel any racial connection with arains, gujjars or rajputs and vice versa because they had just settled in their current locations exactly the same way as the kashmiris, pathans, balochs or syeds from iran and centra asia have done in later times.