Long range attacks are much harder IRL than in SE4.
1/r^2 effects are very very nasty, even if you neglect the time-to-target factor. The linear falloff in SE4 does match its 2D nature though.
If money is not an issue, why scrap old warships and then build new ones? Just build new ones and upgrade the old.
Having very long build times (how many years to build a galaxy class?) also means you do not want to throw anything out.
Warships are not like paper plates and plastic cutlery.
...
Unless you choose the "disposable society" culture in CBmod
