A lot of sentiment seems to suggest that for Lemmy or the fediverse to succeed Reddit has to fail.
I don't get that opinion at all. Reddit had become overwhelming bloated. A popular thread would have thousands of comments. Most of which would be near identical. Only the most up voted would ever be read and typically they had to have been commented while the thread was new.
The internet is vast, there is plenty of room for multiple social media to exist.
If you dislike what reddit has become then ignore it. If you still wish to use it then you can do so side by side with using Lemmy.