I have spent a lot of time reading and chatting with pub-focused communities. The reasons why they don't wish to play is obvious and a whitelist is not one of them. Or at least a major factor.
Pubbers don't like the fact that they can't play their favorite classes all the time. Do unlocks even fix this issue? I would argue they mostly don't. Making engineer & heavy stronger at defending and pyro barely any better at being aggressive does not enhance the game. The classes are too wildly unviable and immobile. With unlocks, people still can't play their favorite classes 24/7. So the answer is no to this question.
Pubbers don't like how the top level of comp tf2 is represented. Yes this is honestly an issue I hear very often. A majority I have seen speak say competitive tf2 doesn't look fun to enter or even rewarding. You have b4nny streaming Froyotech, who almost fuck around in scrims constantly. You have new players enter pugchamp believing it is the beginner website, only to be vocally yelled at BY top players and even mediocre level players. This all is ALSO streamed by various people. I honestly don't think I should be told I am one of the nicer people in Invite while many can still vouch I am an asshole. Do unlocks fix this issue? Obviously not.
What is the incentive? Do you guys think just wanting to be good at tf2 is enough for people to try their hearts out for no reason? Why waste the energy on TF2 when you can literally do it in anything else? Obviously making a good, consistent, rewarding system outside of what ESEA has is extremely difficult to do. ESEA also still costs money. It's absolutely amazing that they got rid of the Open fee but, it still costs money. Much cheaper which WILL help but it not being completely free is still gonna drive people away. Are unlocks going to fix this? Again, obviously not.
With those paragraphs I have stated, why do we believe unlocks are the way to go? I know I use to have the mindset that unlocks should be allowed but my mentality back then was more "why not they really aren't that bad." I still don't think they aren't that bad, but look how much people who ACTUALLY PLAY don't want them. Why should we neglect these players for ones who aren't even here? I've been trying to think about this unlock situation as hard as I can only to come to terms that, yeah they aren't gonna do anything. Which is what a majority has been saying.
Are you guys looking for data? Do as I mentioned earlier and make a cup with actual incentive so people try. People won't threaten to quit the game this way, and valve can see plainly see why we don't want to play with these unlocks. Even theory crafting some unlocks can prove why they just aren't good for competitive. All in all, we have much more problems stopping people from playing competitive. These unlocks won't do anything besides bring Elite Pyro Guild TommyTwoFlares to potentially play and just quit anyway because of all these other issues potentially stopping them.