A Ball of jargon approaches! From a system engineering standpoint we are looking at the tech tree representing a quasi fixed amount of research to complete. I shall call this quantity "total tech yield." The question posed is dealing with players finishing the game too quickly by leveraging several methods. Note that when I talk about tech i'm referring to both science and culture trees. Making techs cost more, and thus increasing the requisite total tech yield for a given level of progress, is considered barbaric and taboo by @acluewithout . He has spoken. We observe that overall tech rate depends on tech rate density (how much science you can extract per area of your empire) and tech rate area (How much area you have making science.) We also observe that tech rate density depends on tech progress, IE you can achieve more science per area with later game tech than you can earlier. We also observe that tech rate area is a joint factor of how much area you control and how much of that has a tech rate increasing district/buildings. What we want is to shift some of the subfactors affecting tech rate area and density, from being a function of tech progress to being more dependent on things which are themselves of a function of time. The question of whether or not the science and culture buildings give you too much yield is a discussion people can have. I personally think they are abhorrently efficient and should be revisited entirely in their design. But I will avoid that for brevity. Specialists take pops. Pops require food and growth, which requires time. Shifting balance of yield from buildings to specialists may increase dependence on critical tech factors with time. Half of rationalism is tied to pops and thus, time. But not the other half. I would almost rather they boost specialists or at the very least come with an increase in maintenance, which ties into... Increasing the economic cost of operating tech rate increasing districts/buildings/specialists will require more other things to support it than it does now. While this reduces tech rate area by limiting how many campuses you can spam, it also ties tech rate area to a sufficient economic base, which requires time to develop. If you needed 3 cities worth of CHs and trade to support 2 cities worth of Campus+TS, then you have radically changed the paradigm. (Example ratio, of course.) In short summary: We can influence tech rate density by just changing the numbers on buildings and districts etc. We can influence tech rate area by increasing the economic cost of supporting tech rate infrastructure. We can influence the rate of change of tech rate density and area by tying more things to time based systems like pops and eras. The last point matters because total tech yield is the integral of tech rate, so of course, reducing the derivative of tech rate will have a stronger upstream impact on tech rate than just cutting it directly. this is because tech rate scales with itself, so retarding the snowball has an increasing delay on achieving the needed total tech yield. i could give much more specific example implementations but that's my eye in the orbital layer view of this.