I suppose I do know bits and bobs about singing because me and and most members of my family are trained in playing Indian musical instruments. And then after that, playing in a group was the next step... and so I'm constantly exposed to singing and singers.
Being a religious guy, I used to sing bhajans but the thing is that it was mostly with a bunch of people that like myself, do not have singing voices at all. One was classically trained but other than her there was no one that sang well. But the thing is that in these cases we "sang" (I use the term loosely) not to show others, but just as part of devotion to God. Now that I'm older and that my voice has cracked to the point where I constantly sound like a kutta with a sore throat, I stick to just playing music 😃
With dancing, whilst I was bad at the start, I never felt that I couldn't do it... I just accepted that I was very bad to start off with.
So whilst I do definitely agree that all art forms are definitely tough, I'm still of the view that because prerequisites can be different, they can also differ in terms of difficulty.
Overall though, I will say that I do see the point that you are putting forward and because you have provided reasoning with your views, I understand and respect them 👍🏼
God bless.