We might momentarily get a new #3 for like half a arc but those spots will forever go to zoro and sanji. If Yamato and loki joined oda would just make sanji and zoro strong enough to be stronger than them. That's why jinbe didn't join in fmi as 1 could argue he would have been the strongest on the crew at the time. Also why Yamato didn't join in wano cus she's clearly stronger than sanji and nigh equals with zoro in wano. At absolute best we may get 1 being nigh equals with sanji but neither will be clearly stronger than him. The m3 will always be there with the only thing happening is there maybe characters strong enough to join the ranks standing with them not subverting it.
								
				



