Simples. In a way you could consider the use of Reddit as a measurement of lesbian existence as, in itself, androcentric.
Reddit, as we know, is full of men. Even before troonism took off. Any lesbian subreddit's existence was at the whim of the male majority, who just as easily could have used "/r/lesbian" as a porn category and not as a community space. That it ever existed before it was pillaged by trannies is mainly a whim.
This is a general rule in 2021: any community that attracts mainly men will contain more trannies than women. Obviously. Turning actuallesbians into a space for trannies is just cedeing to the needs of the larger portion of the community.
It might be more sensible to examine a space like Instagram, where women actually go, to determine if lesbians are still out there.