Oof, I mean, CGI can go a long way, but still... some actors stay young-looking (Johnny Depp did, for a long time), but it's a large cast and not all of them will. And they have to do it for an entire season, which gets expensive.

But, we'll see. My money's on a fast-forward into the 90's, like someone else suggested.

Honestly it’s not that hard, they just use clothing and makeup to disguise their height and age. Works really well for the most part.