I hope Frederick is going through the comments... so this one is for him:

I understand that you've been facing issues and of course, it can't be easy to provide support to a lot of thankless jerks who somehow believe that it's their birthright to get the free support. As a business owner I do understand the challenge of this massive scale can't be easy.

I think - W3TC did what no one else could. It provides features that even best of the caching plugins fail in doing so - there are hardly any commercial ones out there.

I think its time to take hard calls - look at WPRocket's model ( preloading cache bot - proof that people are ready to buy stupid stuff) - reduce the features of free version and put them in the pro version. May be add redis cache as a PRO feature.

Making the github repo public is also a good choice but i'm not sure that how many plugins actually get commits from other developers as much as WP itself gets.

A big thankyou for doing what you've been doing with w3tc all this while! God bless you