The focus of my comment was not a comparison with other relevant provinces but relativize and contextualize Baetica urban decline mentioned in the article.

However Africa was not significantly wealthier and for sure not more urbanized than Baetica in the specific period I mentioned: from Caesar to Antoninus Pius. During that period Africa was less influential in long distance trade, less relevant culturally or politically and in regard urbanization rate Africa province's was lower at any period (maybe you are confusing "bigger cities" with urbanization, but those are different things). Africa, Syria and other provinces grew exponentially in most contexts on a later period, just when Baetica declined, since late II and during III century CE.

The first roman colony outside Italy was Italica in Hispania Ulterior (later Baetica), the first provincial citizen to reach the position of Consul at late republican times was an "ulterior" too (Cornelius Balbo), the first heyday of provincial latin authors had a clear prevalence of baetic origins (Seneca, Pomponius Mela, Lucan, Columella) and the first emperors with provincial origins also came from Baetica (Trajan, Hadrian). All those examples are consequences of a major political, economic and cultural relevance and specially of an earlier/deeper urbanization and romanization. Baetica and Africa had different relative development peaks during Roman Empire, earlier in Baetica case as it was its relative decline.

In regard urbanization, which means relative relevance of urban life, percentage of total population living in urban centres and not which place has the "biggest cities", Africa despite including a big metropolis as Carthage and other few big cities, had still predominant rural population as many other places of the Empire, which doesn't seem to be so clearly the case for Baetica. Guadalquivir Valley (Baetis river) and the area around the Strait of Gibraltar (fretum gaditanus at roman times, "Strait of Cadiz") had a constellation of middle cities that Africa lacked by our current knowledge and those 200 proper, but moderately sized cities probably concentrated way higher share of provincial population than in most other major provinces in the Empire. Only considering the roman cities in Baetica we already located and studied/estimated their limits, barely half of the total, they extended for close to 4000 purely urban hectares. That's bigger area than Alexandria + Antioch + Carthage + Ephesus, traditionally considered as the largest metropolis of Roman Empire after Rome (in that order, Carthage never was "second only to Rome"). Population density was lower in small or medium cities than in the mentioned metropolis, but still the very dense Baetica urban net could be hardly balanced by its rural population, considering the relatively small area (approx 80,000 km2, much smaller than Africa), the existence of large low density areas (Sierra Morena and Betic mountains, over half of Baetica surface), the dominance of latifundia in the countryside and the lack of dense enough rural settlement, so prevalent in Africa or many other places of the Empire.

We have the mentions in literary sources too. Roman period authors mention more (proper) cities for Baetica, for example geographers lists (Pliny, Strabo, Pomponius Mela) or oldest/higher amount roman colonies and municipia of roman/latin rights than in Africa or any other place outside Italy.

In regard "wealth", Baetica was not only mentioned far more commonly than Africa in literary sources from the period we discuss, but archaeologic data demonstrates Baetica prevalence in some long distance trade contexts on western half of the Empire during I and II centuries CE, not only in the aforementioned Monte Testaccio in Rome, but by the fact the most common foreign amphorae found in Britannia, Germania or Raetia were also from Baetica, transporting products from that southern Hispania province.

Africa on the other hand was not the "breadbasket of Western Roman Empire" and much less alone. The contexts of grain distribution mentioned in literary sources focus on Rome city alone and its Annona system, not normal trade nor territories outside Rome city. Egypt or Sicily were also as relevant for this specific grain route as Africa was. On the other hand we lack the evidence for long distance trade relevance on african products that we have for Baetica in this period (amphorae and their tituli picti, mostly, but also literary or epigraphic mentions), Africa trade would only rise to prevalence later, since late II century.