About the automines, habitats etc. . .
I think this isn't issue of costs, it's an issue of availability - by which I mean that
automines and
mass drivers are so damn convenient that having them available
at all instantly makes other mining technologies obsolete and pointless. It doesn't really matter whether automines are 20 %, 100 % or even 300 % more expensive than habitats - they are simply so good that I am willing to accept the cost. They will always be the better choice.
It all comes down to what Zincat says:
Not so a colony, which has to be defended, manned, garrisoned and most importantly cannot be easily relocated for whatever reason.
Imagine you had to (1) use only manned mines and (2) transport everything back home in freighters. This requires huuuuuge logistic chains with shipyards, freighters, tugs, fuel refineries, military for defence etc. etc. These are complex systems prone to cause troubles. But the moment you can build automines and mass drivers, this enables you to skip logistics almost completely. No longer you have a complex system that needs to be maintained, it has been magically handwawed away. Mining becomes "fire and forget". So convenient.
Imagine the game instead worked like this:
- In the early game you can only build manned mined and you don't have mass drivers so you need to transport everything manually.
- Later, "asteroid mining modules" become available which eliminates some trouble with setting up colonies and allows at least some automation.
- Even later, you can research automines, which have asteroid mining modules as prerequisites and are very expensive in RP. That's because they make the previous options effectively obsolete.
In a separate research chain:
- At some point mid-game you can research early mass drivers. There are extremely expensive to build (or perhaps have certain requirements for the system body?) so they are ineffective to build at every moon and asteroid. Instead, you build one for example in the whole Jovian subsystem and then use freighters to shuttle minerals from nearby moons to the mass driver.
- Only in late game, mass drivers become cheap enough (or the requirements become loose enough) so that you can build them everywhere.
The overall effect:
- Early game civilizations have to rely on massive logistic chains based on freighters and manned outposts. Slowly as the technology progresses (and your empire grows), this becomes more hands-off and automated. Only in late game (with a large empire) you will have fully automated chains with mass drivers and automines.
Obviously, this is all very much IMHO. But I am convinced that automines especially, and mass drivers to a lesser extent, are simply so good that players will rarely have reason to use anything else. These two technologies together are making many other game mechanics useless, and in extension, making the game less interesting. Which is exacerbated by the fact that they are freely available from the beginning.