Maester Steven, do you think there’s a reason that Essos lacks a comparable institution of higher education to the citadel given how they are comparatively far more developed than the seven kingdoms? And if so how do you think it would develop? I’d imagine that it would be much more a centralized place of learning for the children of magisters and other free city notables than the lifelong monastic commitment of the citadel. Probably with atlesst one existing in every major free city.

I’ve discussed this before here, but given their level of technology and literacy, Essos must have more of an education system than is shown in the text. 

There’s a couple possibilities:

• Greco/Roman slave-tutoring: this fits the Free City’s social structure, even if that social structure isn’t super well-suited to their level of technology but w/e. Well-educated slaves tutoring the elite philosophy, rhetoric, and the rest of the trivium and quadrivium is certainly a long-lasting “successful” model of education, so there you have it. 
• Local Academies: This is more likely in Braavos and Braavos-centric cities that don’t have slavery. I wouldn’t be surprised if the Essosi academies are A. more focused on Valyrian “humanism” as opposed to the Citadel’s relentless focus on empiricism, and B. more focused on applied sciences needed for finance, commerce, and high-end manufacturing than the Citadel’s trade-school-approach to feudal administration.