Japan is a classic? It (the tarmac rally) has never run in the WRC

Rotation is tricky for rallies because arranging a WRC event requires a big organization, some of it working all year, and it's difficult to take it down for one year out. Same with partner contracts, easier to make multi-year arrangements. Yes, stepping down to ERC for one year is one solution but for some rallies it works better than others. Some rallies get more funding from a motoring club / government while others are dependent on spectators. I don't think we would ever see ERC Rally Finland, it wouldn't just be commercially possible.