It's really hard to say.

Producing documents for publication is a big part of the reason for using software like TeX, both because of its capabilities and requirements of the publisher. Given the audience of TeXmacs appears similar to that of TeX, in terms of capabilities but not the requirements of publishers, it was not terribly appealing to a wide audience and a significant factor holding it back for its specialized audience.

That said, the name did encourage me to at least look at it back in my university days (a very long time ago). When I found that it was not a front-end for TeX, I simply moved on.