Reddit won’t be finished for a long, long time. They could literally start charging $10 a month to use their site and at least half of their user base would probably stay. Ideally Lemmy will one day be a proper competitor, but even then Reddit will live on.
People are always talking about how “X is finished because it made a horrible business decision”, yet they always live on. YouTube, Netflix, Discord, Twitter, Facebook, Reddit… they’re all still doing just fine.