It seems pretty unusual to say that the life of a Roman era subsistence farmer is only superficially different from modern life:

Society doesn't change very much except in superficial ways. Daily life is more or less the same.

But if so, then what features make the agricultural revolution a 'new future' or big change but not the industrial revolution? Relative to the Roman Empire today:

• World population is 20 times larger
• Per capita GDP is around 20 times larger (around 100 times in rich countries), so world wealth is around 400 times bigger; the hours of work needed to buy the bread to survive has declined by a similar margin
• Life expectancy is about 3 times as great
• Humans today are dramatically taller than in Roman times, and have far lower rates of brain-impairing nutrient deficiencies
• Education and literacy levels are tremendously higher
• We consume an array of incredibly rewarding and tempting superstimulus entertainments, foods, and so forth (their attraction is shown in the behavior of those from isolated cultures exposed to them, among other things)
• We can travel around the Mediterranean hundreds to thousands of times as rapidly and at the cost of a comparatively miniscule portion of our incomes
• Communication is effectively instantaneous worldwide
• Our wealth is reflected in lower levels of cortisol, an objective measure of stress
• In most of the world we don't need to fear death by plague or starvation as in Roman times
• People in Roman times were overwhelmingly farmers working long hours raising crops for subsistence; we work mostly in occupations that were nonexistent or much less common, work far less, have the option of working less than we do without threat to survival, and otherwise spend our time quite differently
• Our mix of leisure activities is far different in addition to our work
• We are taller than the Romans, due to better nutrition, have our teeth, effective cosmetics, are clean, etc
• Arithmetic computations are more than a trillion times cheaper than in abacus days
• We have many awe-inspiring near-magical capabilities that would amaze the Romans (all the world's libraries in tiny containers, travel to the Moon and the bottom of the ocean, GPS, video recording, instant language translation machines, bombs that destroy cities, self-driving fast horseless carriages, automata performing many household tasks...)

Why was agriculture a bigger deal? Farming did not increase average wealth or provide amazing capabilities in everyday life (it was often bad for height, life expectancy and other per capita physiological measures). It rooted people more tightly to the land (but transport changes have been enormous, as discussed above). It increased population and population density dramatically, as has happened since Rome. It changed typical government structures (as has happened recently) and activities. It increased construction (but modern cities and structures are better, bigger, more numerous).

I don't see the distinguishing feature.

By and large, the coming century is viewed by future history as not particularly unlike those that came before.

Historians already view the last two hundred years as drastically unlike the previous thousands of years.

Intelligence amplification doesn't happen or doesn't yield generally useful results.

Why would intelligence amplification or robust AI qualify as fundamental changes if the changes since Rome don't? We have much larger, better fed, better educated populations for more geniuses to appear among and incredible tools to enhance their productivity and communication. We have also been changing genetically in response to the changed selective environment of agricultural civilization. Smarter humans would still have heads, use language, eat, have sex, and so on, so why would that be a fundamental change? They might have different jobs and leisure activities, but we differ from the Romans in that way. If increased wealth, life expectancy and technology didn't count in the past then why would further gains from inventions of more intelligent people count?

The intelligence explosion doesn't happen. AI continues to advance in much the same way that it has for the last several decades. More human-capable tasks become automated, but in slow and predictable ways.

By the same token, what changes from AI would count as fundamental?

but these metrics strike me as fundamentally lacking in the context of hedonic treadmill theory.

Would super-anti-depressant drugs or gene therapies that made people have very positive affect for extended periods cheaply, and without serious side effects or effective legal restrictions, count as fundamental where all the post-Rome changes don't?