For curiosity I monitor data on updated and created repositories on Github for different programming languages. Elm’s stats have been steadily falling for 7 years now, peaking at more than 400 new repositories every month in late 2017 and falling to about 50 today.
Google trends shows a similar pattern.
Just an anecdote, but I remember r/elm being at least in the top 5% of all subreddits a few years ago. Now it has fallen instead of rising (7%) and the number of users rose from 10K to just 11K in a significant amount of time.
None of this counts as a definitive judgement on Elm’s popularity by any means, but it shows a trend.