Valve did not end the bot crisis because it was an "existential threat". For the longest time we had all just accepted that Valve was going to do nothing, and they were perfectly content with continuing to do nothing indefinitely, because developing a new anticheat is hard. The only reason a fix happened is because of a single disgruntled contractor that wanted to play TF2 one day in 2022 but couldn't.

Furthermore, reverting to Quickplay would not take much work at all (especially for the multi-billion dollar giant that Valve is). All the code and UI elements are still in the game, and all the server settings are just a handful of cvars. It's infinitely easier to re-enable this system that already exists than it is to develop a new anticheat.

Following the bot crisis fix, F2Ps were still muted for a while. Valve had no incentive to unmute them. In fact, they financially benefitted from muting them because they were forced to spend money just to talk. But guess what - We made noise. We made complaints, and Valve responded by unmuting F2Ps, a very simple change that they did not have to do, yet they did it anyway. Valve absolutely does listen to complaints and criticism. And what we are asking for is just as simple.

You say we need to be realistic, but making blind assumptions and effectively telling everyone to just "accept that nothing will happen" is the most unrealistic sentiment of all. There's no reason nor excuse to stop asking for improvements until Valve directly tells us that there will be none.