We are just making A/B Tests from many designers. And as you see in picture below
There are mainly your thumbnails and one form other. Why? Because again, we are doing A/B thumbnails tests. As your thumbnails gians more views for us, than we order from you.
For example, if some designer comes to me, and says, ok let me make for you one thumbnail and see what my thumbnail can do in A/B tests and if it passed and win's over you, then of course, we will take 5 thumbnail pack and analyse why his thumbnails does better results. And if you after time again come to us, and give as us new style, new identity, and it blows youtube thumbnail TOP 10, then yes, of course we will take new pack from you
I hope I described this process clearly for all of you.