I think this discussion has hit on something. Learning in the past for most was not done in a library. If you wanted to learn something you went to the person that knew the thing that you wanted to learn.and you apprenticed. Or you learned simply by trial and error and then the light bulb moment happens and you figured a better way of doing something.
Most of mankind for most of human history has been illiterate. It's not the eurekas that are the problem it's the library/university that's the problem. Early tech should be aided by activity and not be library/university driven. Every time something is built it should contribute to knowledge whether it is by build queue or by worker. Defeat an opponent in battle should contribute to knowledge and not just experience points for the unit. Discover something or meet someone new should contribute to your knowledge.
Ancient libraries should be changed to what they really were and that is an archive. They should add to culture and or economy. The University should probably become the first building for the campus district probably with guilds I'm guessing, but maybe sooner. Before that libraries should be wonders because they were mainly private and for the literate.
Well, yes and no.
The earliest libraries that have been discovered (Nineveh and Ebla) date back to 7th century BCE and were definitely 'archival' in that the bulk of the materials seem to have been lists of trade goods, warehoused military and construction materials, records of government decrees and diplomatic records. On the other hand, the Assyrians also collected literature both religious and otherwise, and the Egyptians quite early included 'novels' or purely known-to-be-fiction literature.
And while the bulk of the population was illiterate until, in most states, Industrial Era (and, I would argue, is reverting to 'Willfully Illiterate' in the USA today) in Classical Greece, Rome, and China the upper classes were virtually Required to be literate: if you were not acquainted with the 'canon' of cultural literature of the society, you were simply not part of the society or government. Consequently, as early as the 5th century BCE several Greek city states had Public Libraries, open to all citizens of the city, and within a hundred years there were specialized Philosophical and Technical libraries open to the public.
BUT you have a good point: the Tech Tree now combines Scientific with Technical Knowledge: that is, Why Things Work with How To Make Them Work. The former requires influence from as many people as possible thinking about Philosophical and Scientific Principles and sharing that thinking (libraries and other institutions) while the latter is based on attempts to make things work and work better by thousands of people engaged in their daily activities.
I think that the Eureka system, properly engaged, provides the basis for the latter: if you do certain things, they should lead you to do other things better, it's just that now the Eurekas are too often only distantly related to the process they are supposed to 'Eurek'.
For the former, if we assume that Literacy rather than Archive is the basis for Learning, then the library should probably be replaced by the School. The problem is that a lot of the ancient/classical 'literacy' came from in-home tutorial schooling, not easily reduced to a Civ Building.
Some possibilities:
Scribal Schools (frequently associated with Temples in Mesopotamia, Egypt, dating back to 1500 BCE)
Academies (Classical Greece)
Another possible 'Boost' to learning would be the concentrations of workshops found in classical Greek, Middle Eastern, and Roman (and Chinese) cities: streets or 'quarters' where thousands of artisans were concentrated in the same industry, virtual factories' where armor and weapons, wood, leather, cloth or metal work, jewels and other decorative work, all were done. This produced both increased Production but also a 'fertilization' of new techniques, like specialized decorated pottery in Greece, dyed and decorated clothing everywhere, specialized armor and weapons in Rome (which in early Imperial times, also had real armament Factories with hundreds of workers doing coordinated work on weapons and armor for the Legions)
As for the Campus District, this is obviously an artificial game-construct. With the possible exception of the Imperial Libraries of Assyria and the concentration of philosophical 'Academes' in Athens, there just wasn't any such thing as a 'learning area' in a city until the late-Renaissance University, and even then aside from the university itself, the most common other buildings in the area were student bars and brothels rather than Libraries! I can live with the 'Campus' as a place to concentrate Schools or Academies until the University arrives, just to keep the Science part of the game in line with the other Game Mechanisms.
On the other hand, the real beginning of the Renaissance, I would argue, was not the Fall of Constantinople, but the advent of the Printing Press: within 50 years after Gutenburg's first effort, there were presses all over Europe, and the vast majority of the books being printed (aside from Bibles) were non-fiction 'how to' manuals on everything from Agriculture to Mining to Zoology. This provided a Quantum Leap in the spread of practical knowledge which in turn led to a literal explosion of applications. Right now, the discovery and application of the Printing Press is pretty much a minor 'blip' in the game. It should be Huge for your Tech Tree progress.
