What's likely is endogamous units will become larger.
30 years ago, marriages between sub-castes / sub-sets were rare
Today "sub-caste" criteria is seldom insisted upon in Urban or even semi-urban India
So the units will get larger
Fewer castes, larger ones
Especially among those upper caste males left behind in the moffussil regions and not doing well
Women want to marry men better educated / more "well to do" than them
And this will make things tough for those males in "high caste" communities who are living in small town India and not doing too well
And that's where the relaxation will kick in.
But in the example I mentioned (small town poorly educated UCs ), even arranged marriages will turn "inter-caste"