Not sure how many recall it,but Kohli officaly took over permanent white ball captaincy only in 2017, 2 yrs after MS resigned from tests.
In this 2015-17 period India test stocks went from 1 win in 15 tests to 15 wins, 0 losses in 19!
White ball cap seemed a natural progression!
If it was, then Kohli wouldn’t have become captain after MS 🫢