There is not a "huge chunk" of the theoretical physics community working on string theory, and their never was. For one, it is far less common a topic of research now then it was earlier when it was more popular, but even then "huge" was really "a lot of universities had a grant for string theory investigation because it looked promising".
It mostly hasn't worked out and now people are moving on to other things.
The single worst thing that happened though was the populism: a small group of people with credentials started putting out pop-sci books and doing interviews, well in excess of what their accomplishments should mean. People are like "so many people are working on this" because there were like, 3 to 5 guys who always said "yes" to an interview and talked authoritatively.
Huge is a subjective term, but go and count the number of participants at Strings 2025 [1]. Then realise that is just one of many conferences [2]. It's still a very big field.
[1] https://nyuad.shorthandstories.com/strings-conference-abu-dh...
[2] https://www.stringwiki.org/wiki/Conferences
A meaningless statement if you aren't going to introduce any points of comparison. But I would hardly call 735 conference participants a huge conference. Like, that's big but there are lot more then 735 theoretical physicists.
Claude tells me that there are about ~5000 theoretical high energy physicists actively publishing as tracked by INSPIRE-HEP (the de facto search engine in that field). If we estimate that about a third or half of string theorists take part in Strings in a given year -- because there are other big conferences like String Pheno that will be more relevant for many -- then we have something like 30-50% of high energy theorists working on string theory.
I agree that people should be "moving on to other things," but I'm not seeing the evidence that they actually are.
Are all the attendees of a Linux conference Linux developers? Are all the people who attend CCC penetration testers?