Van dijk is not 3 inches taller than laporte hes probably the same height as rodri. Hes also not that good with the ball at his feet laporte is way better with his feet imoUnless he's going to grow 5 inches, he's never going to be like Van Dijk.
What makes Van Dijk special is the fact he's technical, rapid and 6'5''. Small technical defenders are not that uncommon.
I like Ake and wouldn't complain if he signed, but he's not the transformative presence that someone like Koulibaly could be, and because Bournemouth have PL money it probably woulnd't be much cheaper.