I get that, but it is irrational. They can plan such a thing, esp. when they do it in concord consort. Just prepopulate the new lemmy communities with some content, ask some regulars/power-posters to become active first. Then setup a site that simplifies the signing-up tot lemmy/kbin and make a big announcement before you abandon reddit. Sure, at first the amount of people will decline. But as Reddit will have problems assigning new mods to all those big subreddits the quality over there will go down further. It won’t be an easy or even fast switch, but sometimes it’s best to just start over.