[douglas]

Building weapons platforms at a warp point requires a planet in the sector, which is not likely to happen unless someone deliberately made it happen with stellar manipulation tech.

Bases take a lot more effort to set up and cost maintenance. Building defense bases on a warp point is essentially admitting that you have a powerful enemy on the other side of that warp point that you don't expect to make progress against for a long time (or that you're paranoid and willing to spend major resources just in case). The combination of that and being able to hold off that enemy long enough to build the bases is pretty rare, whereas mines and satellites can be built anywhere and then deployed almost instantly anywhere else if you have ships to deliver them. That said, when that unusual combination of factors does come about, a pile of starbases does make a formidable defense. I once had 8-10 starbases with Massive Base Mount Ripper Beam IV's and 9000 phased shield points plus tons of PDC's sitting on a warp point in a stock PBW game because I was fighting two powerful enemies at once and didn't have the resources to advance on both fronts at the same time but did have enough to just hold my position, and they tore through the next fleet that enemy sent quite effectively.