Certainly not in solar systems.In galaxies.
One suspects in every (older) galaxy, except those in phases of formation.These black holes are then only active and grow as long as material is nearby, since the gravity is not amplified by black holes, but only concentrated, the external effect on all further outer solar systems is the same as that of the previous solar systems. distributed solar (systems).
Potentially, suns can end up as black holes, but not all CVs end with it, it needs heavier suns than ours, not because too light black holes are unthinkable per se, for each mass a black shield radius can be calculated, but because the existing mass needs to be compressed smaller and requires an energy that cannot come from too small suns.The event horizon must be outside the body of the black hole, so that the phenomenon arises that something can come so close that it no longer comes out. The inner matter, which still exerts its gravity outwards 1:1, as before as the sun, can only increase in principle, unless antimatter reduces the inner matter (this is the mechanism of Hawking Radiation).
The end as a supernova with enough solar mass can mean that the implosion of the supernova explosion can compress the core of the sun so much, because it provides enough energy to combine electrons and protons into neutrons and that only allows that this matter becomes more compressible.This can result in a neutron star and, with even greater compression, a black hole. As already mentioned, this does not make gravity any greater, so the planets of such a solar system may still exist and are pushed out of their orbits rather by the influence of the explosion of the solar envelope than now the first fodder of the newly formed black to become a hole.
In the interior of galaxies, however, the solar system density is greater, so that in the long run solar systems can converge, and thus certainly become unstable in many cases as far as their planetary orbits are concerned, up to the rare hit that a sun in the area of influence of the black hole.The smaller the black hole is, the more likely there is not just a single fusion event, but the sone is slowly consumed and such a constellation is called quasar, but usually this is not due to two coming too close Solar systems originated, but happened in a double star system, in which one became a black hole. In any case, however, a small probability of a solar system approximation is sufficient, that this happens seen over sufficiently long periods of time. And so, gradually, only a supermassive black hole is created in the inner part of a galaxy, and that is something that has no rarity value, but is a logical consequence of the r茅sum茅s of suns and the density of solar systems in galaxies.