only way built bases would work is if the original bases placed are far better...and the built bases would just give a position advantage...otherwise yes everyone would just forget about the originally placed bases...
That idea could work with the "already out there" outposts of course, and I like that idea, it wouldn't be an outfit attempt, it would be a faction attempt...or empire...or whatever you wanna call it
It works that way in asherons call as well, there are castles (that have to be rebuilt...) and you can do things such as place turrets (yes..there are turrets in asherons call...don't ask...) build walls, etc...I think this concept would be a good idea for bases in PS. Things like upgrading turrets, making base harder to hack, etc would be a good touch. That way all bases aren't the same and a hacker who knows his way around them can get straight to the console and hack it, knowing where the base defenses are...It gives it an unpredictable twist which would make recon a much more useful role.
A game that you can't modify to your liking...is not a good game...