they don't transition from sudhra they faked the geneology
'And that's unique to South Asia's Caste system?
Anyway like it brings back to my point that caste system is thing that's unique to India, the 5 ranks stayed the same but the Jati ( communities, tribes, clans what have you not) made up those ranks, kept moving up and down depending upon what they did, so a Jati moved through a rank, so the Brahmin or the kshatriya would not have any meaning without the Jatis that constituted those ranks, so a "Shudra" cannot move up the rank because a Shudra is not a Jati, a Maratha is a Jati and they moved up to become Kshatriya, a Shudra is a Rank.
And these Jatis are basically extended clans system, you kept track of membership through kinship and marriage. In Christian Europe with Tribal Kinship being broken by the Catholic Church by banning even extended cousin marriages, how would people keep track as to the caste of a particular man or a woman, as soon as you break a tribal kinship, family becomes the basis of societal organization and it would require a complex bureaucracy to keep track as to who is who, or may be a rudimentary system like tattooing a man or a woman to indicate his or her caste in the society? that too requires a level of bureaucracy that was absent in Europe at the time, so the entire things becomes a complicated mess in the absence of clan system because at the end of the day caste had a socio economic function too and not just a religious function. It was the basis of division of labour and distribution of production and management of the economy that evolved organically probably from the days of Indus Valley civilization since we find the residence in cities of those civilization organized around occupation, which is why you can't compare the caste system to that of European feudalism. They are different, in their origin and evolution and purpose and the supposed similarities are often used by Marxists to their political ends, and they often ignored the important difference between the two
In feudalism, you as an individual can rise in rank, you can become a Knight or you can become a monk in the church, and your social standing improves, but the members of your community certainly will not improve their rank and they in all probability will remain there.
However in a caste system you as an individual cannot improve your rank in the social standing but your community over few years can improve themselves, and this happened even during the 20the century, where tribes in Himachal got the rank of Kshatriyas by their participation in the British Indian Army and by sanskritizing themselves, so you moved up the social ladder with you community.
which was rejected by Brahmin who refused to crown maratha kings
You mean Shivaji, I mean they crowned his descendants as Chhatrapati's. Besides didn't Gaga Bhatt preside over Shivaji's ceremony ceremony while other's refused. So he did find a Patron and by coronating Shivaji other Marathas became Kshatriyas, yes you did have people ( I think Chitpavan Brahmins ?) who refused to recognize it but their refusal does mean that some Brahmins did recognize the Marathas as Kshatriya, remember Brahmins were never a united faction in politics.
As for reasons why it was refused it's not just the caste, there was theological reasons other than the caste and there were pollical reasons too.
what can be done to change the attitude of the church ?
I'm not an expert on Catholic Theology, all I am saying is for a Caste system you need tribes and clans and in the absence of the two you'll just end up with a rigid class system