Jacuribu’s point doesn’t take into account that some planets are worth more to be on, so expanding on them may intrinsically be worth more than building a second base. Also this doesn’t take into account the faster growth of, and better use of, experts in larger bases.
I’m surprised the fall in permit cost from 7 to 8 hasn’t been mentioned. By my maths permit 8 costs 38% of permit 7. The switch from stupid numbers of b-fabs to manageable numbers of more expensive l-fabs causes this step down. Perhaps switching one fab per step would smooth things, and making MCG and TRU rise more smoothly across all permits.
I think longer term a more granular permit system may be the way to go, allowing a range of bonuses, ship sizes and base sizes to be purchased. Switching from 1 permit/upgrade and base to 5/upgrade and base, and a linearly decreasing area per permit based on 5 permits = 500 area and 15 permits = 1000 area as at present, you get the following:
Permits Area
1 125
2 235
3 333
4 421
5 500
6 571
7 636
8 696
9 750
10 800
11 846
12 889
13 929
14 966
15 1000
Note how 10 permits (2 currently) should be 800 area not 750. With a granular system would Jacuribu’s approach mean we all have a large number of 125 area bases, or think more carefully how large we want each base?