How Coby and Luffy will form an alliance

This theory is one of the most wildest theory I've ever heard 300 yrs ago lived a real life pirate named
Edward teach also known as Blackbeard he was known as one of the most notorious pirates in the golden age of piracy ,but his era ended when he was killed by lieutenant Robert Maynard. Now there might not be that much of a chance of this happening but it's still a great theory There is a high chance that Blackbeard will be the final antagonist in the series and the strongest that luffy ever faced probably. The god valley incident that occurred 38 years ago in one piece in which the Pirate King Gol d.Roger and Monkey d. Garp formed an alliance to beat the Rocks pirates in which the rocks pirates got annihilated.Only a few such as kaido, big mom and whitebeard survived so history might repeat itself and we all know that the current generations garp and Roger is none other than Coby and Luffy. So what if Coby and Luffy teamed up in order to defeat Blackbeard although it's less likely to happen since luffy wouldn't receive the spotlight he deserved it still seems a good theory .