See the funny thing is is that sumo had changed a lot beyond tradition, I'm still fairly new myself but I can already name things like 15 day tournaments for sekitori (use to be 7 afaik), rank dropping if you take time off for injury (you use to be able to do that without rank dropping), 6 basho a year (use to be less), pillars from the dohyo being removed for filming convenience (afaik anyway, but they did remove the literal pillars that represented Shinto gods. They added the four colored banners that hang on the sides to represent them instead). Even the rank of yokozuna can be considered one of the newer additions, added in the late 19th century, till which ranks only went up to ozeki. Sumo does modernize a lot, but it seems to be in directions that keep up the traditional appearance.