There was never a strong consensus to redirect people to alternatives like lemmy, so people used other parts of reddit until their favourite subs reopened. And when people redirected, most of them just directed to fuckin' discord, which doesn't serve the same purpose at all and is even worse from the lock-in perspective.
Unfortunately habit is hard to change. It also doesn't help that federation is quite confusing, especially for non-tech people. The apps being pretty much in alpha/beta is another problem. I'm having a hard time browsing lemmy on my potato phone. The website seems as heavy as new reddit. Kbin is a little lighter. Maybe there's another hope when the API is finally dead and the apps become useless.