It's literally how the bgs works right now. The more influence you have, the harder it is.Nothing in the game currently does that. The whole taking more costs more like that. Thats like saying i want 40 sidewinders. The first 10 are normal price but every 10 after that doubles the price and so on. Thats why its a surprise to everyone.
The whole motivation of this though is that there's nothing to be lost to just continually expand outposts... or more directly, there is lots to be lost to pause gobbling up systems with outposts in order to grow the systems you have.
That's pretty bad design imo.
(That is, what would you choose? Spend time building up the facilities in a system to surface a good couple markets with high population, or spend the same effort claiming 20 systems, giving you the capacity to make dozens of such systems.... it's a no brainer right now. )