If you liked infinite ore mods in 1.1, this mod is likely not for you. If however you think Space Age feels too much like an infinite ore mod, you might like this.

Back in 1.1, growing a factory's science per minute output inevitably required the factory's size to grow, because each resource patch could only yield so much. In 2.0, certainly in Space Age, with vast productivity bonuses and quality on top, late game scaling feels nearly asymptotic - so much can be created with such ease that there's hardly a point in expansion, and a single Nauvis ore patch can yield ~100k spm for all Nauvis sciences - simultaneously. With a couple big mining drills and a few hundred levels of mining productivity, so that each drill outputs a saturated stacked ore belt, which in turn yields stellar amounts of finished products because all intermediate steps have double or triple their normal output for the same input. The game thus becomes heavily skewed towards building and optimizing end stage buildings (i.e. science assemblers and labs), which thus outnumber everything else by an order of magnitude (with biolabs becoming more numerous than e.g. foundries). And we end up building a huge array of legendary biolabs with a ton of legendary modules all to process what a handful of mining drills gather from barely-depleting resource patches.

This mod aims to bring back that 1.1 feeling where more output (be it science or something else) requires ever more input, also late game. To achieve this, it restricts how much you can make with limited resources:

• All default quality bonuses are reduced from 1+0.3*level to 1+0.1*level. This affects modules, but also various other items.
• All productivity research is halved (from 10% to 5% per level).
• Mining productivity has exponential research costs (1.5^L, same as most other productivity researches).
• Built-in productivity bonuses are reduced from 50% to 10%.
• Mining drill drain reductions are less pronounced, especially at high quality; legendary big mining drills now have 60% resource drain (rather than 8%).

This will have the following effects on gameplay:

• Main effect: Resource gathering and processing is now also a substantial component of late game factories (comparable to early game), and to grow your output, you will have to keep expanding your territory. You can use modules and tightly packed mining drills to boost output, but patches will run out faster if you do. Meanwhile, productivity modules in mining drills can marginally mitigate resource depletion.
• Similar to 1.1, the bulk of logistics challenges you face are about transporting and processing basic materials, while final outputs (science packs) are only a small fraction of all the materials you need to move around.
• Quality is useful, but not a gamechanger anymore for productivity multipliers. For instance, an electromagnetic plant with 5x legendary productivity modules now has a 85% aggregate productivity bonus, rather than 175% in vanilla space age (and on top of that, legendary productivity modules will also be harder to produce in large quantities with increased resource requirements and decreased effectiveness of high-quality quality modules, so you will end up needing more EM plants while having fewer high-quality modules to put in them).
• Quality upcycling with processing units or low density structures takes far longer to turn into a method for free creation of legendary materials. In vanilla, processing unit productivity 13 is sufficient to reach the 300% productivity cap (with 5x legendary productivity module and 50% built-in), making it free to turn normal quality inputs (or liquid metals) into legendary materials - but now one would need to research processing unit productivity 43 to reach this same stage. As a result, it will take far longer before legendary quality items can be mass produced. (Nothing was done specifically to discourage crusher quality cycling, as the purpose of the mod is primarily to reduce productivity. However, the lowered quality bonus for legendary quality3s (3.75% vs 6.25%) does have a material diminishing effect on the effectiveness of this approach.)

This is my first mod, any comments or suggestions are welcome. I didn't make any of the altered parameters configurable. This mod should be compatible with basically everything as it only modifies a small number of variables from the Space Age expansion (and the base game), so aside from a few numbers the game is not different.