Data points
1) It is still possible to close accounts (at least sometimes, depending on the agent) via Chat.
https://www.flyertalk.com/forum/31054600-post943.html
2) A few weeks back, three members of my team were asked to send in income verification (instead of having a verification code sent by phone). Two of them
chose to not send in the income verification, and so their applications were not approved. Just today they both applied anew, were allowed to receive the 5-digit verification code, were not asked to prove income, and were approved.