I don't think so. Using the Antikythera mechanism as a basis for metalworking ability possible at the time, brass is a suitable material with many small brass engines of various types seen on youtube. The Antikythera mechanism demonstrates high quality bushings and axles, complex gear trains, precision flat surfaces, and soldering. Everything you'd need, just applied differently.
> with many small brass engines of various types seen on youtube
Fair enough. The problem is more that "the Romans had put functionally no effort into figuring out how to make efficient pressure-cylinders, because they had absolutely no use for them."
The author mentions the Romans couldn’t have built [a Newcomen steam engine] without developing whole new technologies for the purpose (or casting every part in bronze, which introduces its own problems)" without expanding on those problems. Presumably it would be material cost of bronze (or brass) relative to "any profitable use to put it to."
So yes, the Romans technically could have figured out pressure vessels. But they had no need to, and so didn't go through the process of refining their materials and methods for the purpose.
