One could suppose it... but there's a little issue that's following William, in that it seems his heart isn't in becoming the future Monarch, and he seem to be withdrawing more and more from public duties...
For example he's only doing a third of the work , that his father did at the same age... ..and his father the King, is still doing more now at 77 years old suffering from Cancer than William is doing now in his 40's...so whether we'll end up with a King William is anyone's guess at this juncture