Failed Stars ????

We have a failed star in our solar system. I is the very large gas
planet Jupiter.It has the right stuff but not enough of it.Its core
can't create fusion,and yet it radiates our more energy than it receives
from the sun.Still a little larger and Jupiter could be a star. This
is not the reason for posting this Google stuff. My thoughts go further
out. I have questions about stars forming from those huge gas clouds
"like" Are there failed stars in these clouds? Could
billions and billions only reach(evolve) to a stage of "brown dwarfs?
Is more to the gravitation center of the nebular the best place for star
formation?(I would think so) I would think the center being more
dense(more particles) that would be the spot to find super-nova
stars,and that means black holes.. Best reason I can come up with for
the center of galaxies having a black hole. Good reason using failed
stars as part of the dark missing matter of the universe. Bert