Matt

Some of his aging was makeup, they made him look a bit older and more weathered. People tend to forget that Wolverine is supposed a fairly rugged character. The older he gets, the more weather beaten looks, the more he embodies the character.

Also, it would not be fair to saddle Cavill in the role immediately after Hugh. The best way to transition the role to the next actor would be after a few years absence, so audiences can properly process the trauma of Wolverine regenerating into a new actor. This would also be the best way to get Wolverine onto the X-Men. If Marvel is smart, they will keep Hughverine as a free agent, perhaps loosely aligned with SHIELD or even the TVA.

This would serve two purposes, 1: It would allow the X-Men to establish themselves without being in the shadow of the Wolverine, and 2: Let Hughverine go on a Grand Tour of the MCU before he enjoys a well earned retirement from the character.