Why?
Steele made the basics and everyone derived from there. Anyone is free to make their own Lisps.
CL was designed by comitee and produced a pretty solid Lisp with huge practical benefits. What CL needs is just better standardized libraries, but most of them are either portable or they're made to work in almost any major implementation making them effectively portable. Some parts would be better standardized, but there's already the CDR (and some other) efforrts going along. Scheme has SFRI which works well for them. Other new Lisps are lead in their own way, like Arc has PG, but he slacked off too much that some people made their own branch...
I think Lisps are flexible enough to become whatever you want them to be, and thus they don't need leaders. They do however need direction and smart and hard working people putting some time into straightening various issues. In the case of CL some of those people were Steele and Pitman.