It isn't a hobby of the past. Arborists are professionals still using knots and studying them (especially with the modern rope materials changing the old knowledge around knots). Rock climbing is a hobby but knots are life-or-death for them.
Knots are still being invented nowadays. Or variants of existing knots.
Here are PACI's systematic studies on a few vital knots:
https://www.paci.com.au/knots.php
Here is a recent (2025) paper on the stability of the bowline:
https://www.epfl.ch/labs/flexlab/wp-content/uploads/2025/11/...
Thanks! Oh I have every confidence we are still studying this, and that it's a thriving field – forgive me for implying that it wasn't.
I was (badly) getting at the fact that back then, as a function of the totality of knowledge we had, discovering a new knot could be quite transformational – whereas now it's just one of many professional fields of modern research. Not implying it was then, or now, merely a hobby.