I assume by unable you mean they had to stop due to persecution? It sounds from this article that this practice that had survived so long also hit an abrupt sto

I assume by unable you mean they had to stop due to persecution? It sounds from this article that this practice that had survived so long also hit an abrupt stop when faced with persecution from colonizers (at least that's why I'm assuming they have to go by records from 1880 and not just ask the current practitioners). I think this says more about the ability for persecution to shut down a cultural practice more than any quality that practice has to have to survive.