I just did some more thorough research and re-calculated the time needed for generating the amount of resources given by Stripped to the Core.
Assumptions: Same taxation level for both, 100% allegiance, maximum population and logistics upgrades present, all slots filled with trade ports. Additionally for shortest time scenario: Maximum population tech of all three races (+15% - +60%), maximum trade tech (+30%), maximum trade route length (+67%). Increase all times by 20% if salvaging is researched for SttC.
- Asteroid: 9-5 minutes
- Dwarf: 9-4 minutes
- Volcanic: 35-17 minutes
- Ice: 19-11 minutes
- Desert: 15-8 minutes
- Terran: 26-15 minutes
The only way to generate more resources without SttC than with it is by stripping an Asteroid. This leaves an Asteroid Belt which does NOT have neutral extractors, so they can neither be captured nor rebuilt. If one type of extractors is not present SttC generates a free amount which cannot be received from this planet otherwise. If extractors are present it takes 11-18 minutes for metal, and 4-6 minutes for crystal to generate the same amount, depending on tech and number of extractors.
Those numbers would be quite balanced if not for the need of a massive inital investment in terms of:
I very much like the idea of tieing it to the Titan, as this would also mean a big initial investment and help enemies anticipate and prevent use of SttC. Would still apply taxation, though.
EDIT: Since all the assumptions are over-the-top optimistic you might want to factor in the economic potential of an AVERAGE planet. I would go for a planet with half of its slots being trade ports, a medium length trade route, 60% allegiance, 30% taxation, no to low tech. So this would mean current time * 1,3*1,4*1,4, so depending on planet type you would need to 20-90 minutes on average to break even with SttC.