Quite a simplistic view on football isn't it. You're looking at defending in such finite terms but it's not about individual ability to win a header or which CB is the best at tackling - the best football teams at the moment are about retaining/winning back possession and working as a unit, especially when you play CB. Simply look at the best defences this season (LPool, City, Spurs in that order), they all play a very different style of football but none of them sit deep. Across those three teams there is a real diversity of CBs; VVD, Alderweireld, Stones, Vertonghen, Kompany etc and you can argue that Smalling is better in many of the basic defensive 'skills' like heading, tackling, marking than some of them but it's irrelevant when you play elite level football. These CBs all complement a certain system, individual quality is not the deciding factor - you only have to look at Lovren for proof of that.
You seem to value the old fashioned English CB - an uncompromising technically limited player at the back who was most useful when facing strikers like Duncan Ferguson, Kevin Davies and similarly physical and aerially dominant strikers.
Ironically your reference to Messi is precisely why I'm not in favour of the counter attacking style in the PL now & why Smalling is too limited. Mourinho is a prime example of a manager who would setup his team in a defensive shape and then leave his attacking players to create, without necessarily coaching patterns of attacking play and how he wanted to attack (Hazard gave a good interview on this a few years ago). Unless you have these very rare attacking players who can create chances out of nothing, you end up playing like we do now with very little penetration or ability to play through the lines as a team. The change that needs to happen starts with the GK & CBs.