The main issue of this model is the assumption that loud aliens are observable out to infinite distances. I am going to go out on a leg an just state that loud aliens are going to be a struggle to observe even within our Galaxy (+orbiting drawf galaxies). And the best that we could ever hope for detection would be our local group. So a lightcone of mere 10 million light-years. This throws the speed assumption right out of the window and allows for VERY slow GC expansion rates.
The main issue of this model is the assumption that loud aliens are observable out to infinite distances. I am going to go out on a leg an just state that loud aliens are going to be a struggle to observe even within our Galaxy (+orbiting drawf galaxies). And the best that we could ever hope for detection would be our local group. So a lightcone of mere 10 million light-years. This throws the speed assumption right out of the window and allows for VERY slow GC expansion rates.
The rest of the analysis is very insightfull.