Is strategic leadership necessary for any organisational head?

Of course. 

I mean, unless you're ok with being a part of an organization that one day will hit a wall and collapse. 

I'm not :) 

Sure it is a must as the top of any organization should has the vision internal and external that enable the company to set objectives for the upcoming 10 years

Yes, mainly in an organization that doesnt have a board of directors. A strategic leadership is completly necessary to dictate the orientation of the future of the company.

Yes.  It is one of the primary tasks of the head of any organisation.