The effects of the Antonine plague in the later half of the second century (ca. 165-190s CE) were far reaching. It is commonly accepted that the outbreak was some form of the Smallpox virus (Harper, 102). Scholars estimate anywhere from 1.5 to 25 million dead throughout the empire over the course of the plague (Harper, 108). This, and many other concomitant factors brought in its aftermath great economic and social upheaval in the later half of the second and long into the third century. The large death toll caused a slackening of the many social and class restrictions due to depopulation. For example, in 174-175 CE, emperor Marcus Aurelius loosened his own requirements for holding office in the city of Athens, that is, membership in the Areopagus. This was because there just wasn't enough "well-born" candidates to fill the ranks and Marcus mentions that this shortage was due to the "disasters" that had occurred in the cities (Duncan-Jones, 134).
Partly due to personell shortages across the empire and partly due to increasing inflation, wage hikes lead to an increasing cost of labor in the third century. The labor shortage and inflation also caused a large increase in the price of commodities from the second to the third centuries (Scheidel, 103-104). The papyrological record from Egypt reveals this increase in wages showing that the cost of rural labor at least doubled from the second to the third centuries (Scheidel, 104-105).
This level of economic and social change should be visible within the material and literary remains of Roman writing and book culture. Already in the third century the writing of Roman law changed quite drastically due to the Constitutio Antoniniana, that is the declaration by Emperor Caracalla of all peoples within the bounds of the empire as Roman citizens around the year 212 CE (Zwalve, 367). There was also a drastic decrease in the number documentary records produced during the last half of the second century (Duncan-Jones, 124-125).
It appears then that the economic decline did indeed leave it's traces in Roman literary and book culture. Raffaella Cribiore, in her work, "Writing, Teachers, and Students in Graeco-Roman Egypt," which focused on the material remains of teacher and student writing samples, noted that the quality of papyrus used in student exercises dropped off after the third century (Cribiore, 58). This corresponds with Turner's observations who noted that the quality of papyrus declined after the third centur, describing it as "resembling cardboard" (Turner, 2). This decline in quality coincides with the drastic increase in labor and material costs mentioned above. For Pliny the Elder in the first century wrote that papyrus paper was manufactured in varying levels of quality and Cicero gives hints that these differing qualities had a proportionate level of cost (see earlier post here).
Though Scheidel's study of Roman-Egypt wage increases specifically did not include the wage of scribes (Scheidel, 105), the cost of hiring a scribe must have continued to increase along with the price of commodities for the Emperor Diocletian in 301 CE gave an edict capping the price on commodities and wages for different services (for an English translation of the edict see, here). The price that could be charged by both a scribe and a notary are listed as follows.
Scribe, for the best writing, for 100 lines, 25.It is apparent that during the third century and into the fourth century, the cost of employing a scribe increased enough so that the cost of producing a high quality book by hand would have increased as well. This cost increase might be reflected in the popularity of certain styles of writing used in the third century and beyond. Cribiore noted that decorated and serifed styles in Greek are found in school hands from the second century BCE into the third century CE in Roman Egypt with only a few examples found after this time (Cribiore, 115). This style of handwriting was referred to as "Zierstil" by palaeographer Wilhelm Schubart and was the subject of a thorough study by Giovanni Menci (see also Turner and Parsons, 21). Menci noted that these types of serifs were used across different handwriting styles and were added to several different hands across the centuries (Menci, 48-50). Menci also mentions that the first and second centuries CE were the high point in serifed writing and notes that the hands that became dominate in the later centuries do not exhibit the "decorated style" (Menci, 49-51). In support of this observation, Turner noted (before Menci's study) that there where few securely dated examples of serifed writing in this "informal round" style found in the third century noting two in the first half of the third century at the extreme end of a four hundred year life, P.Oxy 42.3030 and P.Oxy 43.3093.
Scribe, for writing of the second quality, for 100 lines, 20.
Notary, for writing petitions or legal documents, for 100 lines, 10.
(English translation of edict)
Without knowing for sure what Diocletian's "best writing" is referring to, it might be that, due to the ever increasing cost in paying a scribe to copy out a book, more serifed writing styles ("Diocletian's "best writing") may have dropped out of vogue due to pressures of economy.
Cribiore, Rafaella "Writing, Teachers, and Students in Graeco-Roman Egypt" (Atlanta: Scholar's Press, 1996).
Duncan-Jones, R.P., "The Impact of the Antonine Plague," in Journal of Roman Archaeology 9 (1996): 108-136.
Harper, Kyle, "The Fate of Rome: Climate, Disease, and the End of an Empire" (Princeton: Princeton University Press, 2017).
Menci, Giovanni, "Scritture greche librarie con apici ornamentali," in Scrittura e Civilta 3 (1979): 23-53.
Scheidel, Walter, "A Model of Demographic and Economic Change in Roman Egypt After the Antonine Plague" in the Journal of Roman Archaeology 15: 97-114.
Turner, E. G. Greek Manuscripts of the Ancient World. 2nd edition. Edited by P. J. Parsons. (London: University of London, Institute of Classical Studies, 1987).
Turner, E.G, "Greek Papyri: An Introduction" (Princeton: Princeton University Press, 1968).
Zwalve, Willem, "Codex Justinianus 6.21.1: Florus's Case," pg. 367-378 in "Crises and the Roman Empire" (Leiden: Brill, 2007).