The idea that players should be forced to go to port to upgrade ships comes up from time to time. The overwhelming consensus from players, outside of a few die hards on the issue, is: ABSOULTELY NOT . For many reasons, including micromanagment, balance, and that good ol' fashioned concept of "fun". Micromanagment and balance concerns arise because this would inevitably encourage even more starbase spamming, this time just so people could upgrade ships hundreds of tiles and dozens of turns away from home. The lack of fun comes in because, quite frankly, it sucks to waste 20 turns just so one can put a new set of blasters on a ship, just to turn around and waste another 20 turns to get you ship back where it came from.
Now the devs did consider this idea early in development. But they ultimately concluded, rightly IMO, that there would be a revolt on their hands if they tried to change a long standing mechanic like this. Personally, I shudder at the thought of this being implemented on an Insane map.
Now from an immersion standpoint, don't forget that the whole concept of range is part and parcel of this. It's not just life support, but also resupplying ships after battle, giving them more fuel to travel, and generally everything else tied to the idea that ships can only go so far away from friendly territory.
No, requiring ships to go back to a base to upgrade would require a radical redesign of how ships, range, and distance are currently handled. And considering that there are already disadvantages to upgrading far from home (longer time to do it, more expensive [I think], ship is a sitting duck while being upgraded), I see little reason to force players to waste turns to send ships back home and manymany reasons not to do it.
As for the separate issue of cost, I do agree that it is far too much right now. At least compared to GC II. I'd have to back and check to see what the ratio was before, but right now it is completely out of whack. From what I understand, the debs want players to choose the X-per-turn option when it comes to upgrading. But that sucks as well, IMNSHO. . I am quite certain there is a happy medium where it still costs a chunk of change to upgrade many ships at once without completely bankrupting the player. Just have to find it.