This may be a controversial or unpopular opinion, but I really think the barrier to entry for Colonisation has been set far too low. 25 really is pocket change to claim a system. And we make a profit hauling the commodities required. Personally I think taking on a full system should be a substantial commitment and the claim price should be more like 500 mill.
Price is not a problem, there are plenty (too many) star systems in the galaxy. Most will never be colonized if everyone participated daily for thousands of years.
We need alternative activities to get facilities built. Because hauling for weeks is frankly very boring.