The entire premise of the west indies great teams were that you didn't need a spinner, even the Australian team before that and the South African team before that were predicated on fast bowling.
That doesn't mean that a spinner can be of use, that also means one is a must have for success, because it's been proven that it isn't.
Cricket is made up primarily and historically of the India, Pakistan, Sri Lanka, Australia, WI, South Africa, New Zealand, England. Of those countries spin as a primary weapon has been proven effective in 2, and lead to any firm of dominance in 1. Yet somehow it's being seen as a draw back and a major hindrance not to have a spinner, but not to bee overly reliant on spinners who are only effective at home.
Additionally the only spinners that's been proven effective or even dominant in non spinning conditions vs quality teams are Warne, Murali and O'Reilly. So I don't understand the argument