[yefragetuwrabrumuy]

I truly doubt that many such rogue planets are still about, at least within the galaxies. Galaxies are dynamic things, with all kinds of tidal forces at several levels.

To start with, why is the vast majority of the Milky Way galaxy spinning in the same direction? And imagine how much force is needed to keep it from flying apart.

Yet things are constantly changing in the galaxy. Sooner or later, over the course of 14.5 billion years, rogues are going to meet up with somebody.

[WhiskeyX]

Spiral galaxies collide and settle down into becoming a merged elliptical galaxy with the vast majority of the stars surviving the risk of collisions, because there is so much space between them to escape collisions. There is ample opportunity for the vast majority of the rogue planets to avoid collisions in the same way as the stars. Those rogue planets with a circumgalactic orbit similar to those of the stars tend to avoid collisions in the same way as those intr-galactic star populations.

The by far more numerous population of rogue planets in inter-galactic space would be even far far less at risk of collisions in the vast space outside a galaxy.