Evidence for ET?

[Gawdzilla Sama]

I am to understand that matter doesn't conglomerate in progressively larger chunks? That the smallest such accumulated mass would "likely on average much more massive than Jupiter"?

Jupiter emits twice as much EM as it absorbs from the Sun.  If there were large numbers of Jupiter-sized objects in interstellar spaces (MACHOS), they would have been detected via gravitational lensing, occultations, etc.  Such objects have not been found in large numbers.  Ergo, most large objects form around stars.

Have you counted them?