Not really sure why you think that fencing has "grown", but for example in 1999 we had 15 nations winning at least 1 medal, last year we had 14 nations winning at least 1 medal ...
In my opinion fencing always was a sport where some random athlete from a small nation could win a medal on a good day (like shooting, judo, taekwondo), but i don't really see that as a sign that this is a global sport. At the last 5 regular world championships (2013, 2014, 2015, 2017, 2018) only 13 nations have won team medals (in a total of 30 events), 10 of those nations are from Europe (Germany, Italy, Russia, Switzerland, France, Ukraine, Estonia, Hungary, Poland, Romania), 2 are from Asia (China, South Korea) and 1 is from Northern America (USA) (surprisingly Japan hasn't won a single team medal if my research is correct ... ! ).