Camel caravans have long populated the image that we have of Muslim world, but I've recently learned that, up until Roman times, they weren't as commonplace and/or as important as they became after the Arab conquest of most of the Middle East and North Africa in the 7th century.

One of the scholarly sources that have taught me this is the paper "From Baghdad to London: The dynamics of urban development in Europe and the Arab world, 800-1800", which states that the Arab world focused much more on overland trade than sea trade, with most major Muslim cities being located quite inland compared to the former Roman metropolises, like Cairo in Egypt (in place of Alexandria) and Damascus in Syria (instead of Antioch):

For cities in the Muslim world we do not find this: the sea coefficient is negative, implying that location at sea does not give cities a clear advantage over their landlocked counterparts: indeed, the really big Muslim cities such as Baghdad, Damascus, Cairo and Cordoba are inland (Istanbul is a notable exception here, but it became a Muslim city only in 1453). Also Muslim cities with good access to roman roads are not larger than others. In contrast, being a hub of caravan roads has a strong positive effect pointing to the importance of transport on camel-back in the Arab World.

Instead of old Roman roads or ports, caravan hubs became an indicator of prosperity. Sea trade only mattered in the Indian Ocean, the Mediterranean being a relative backwater for the Muslims:

This appears to have been less the case in the Arab world. Indeed, the Arabs largely replaced the predating Roman system with one of their own, founding many new cities from scratch. As a result, the effect of Roman roads and of (arch)bishops is much smaller (and insignificant). Instead, we see a strong influence of caravan hubs indicating the importance of trade via caravan trails (linking Africa to as far as India and even China) that gained in importance after the Arab conquests. It also, combined with the insignificance of location at sea, shows the orientation of the Arab World towards the East and South (see e.g. Pryor, 1988, p.137 and the geographic scope of Arab travelers [more on this below]). Mediterranean trade was of marginal importance compared to the Muslim trade across the Sahara and in the Indian Ocean.

(...)

The radical change in the dominant transport mode following the Arab Conquests is clearly evident from Table 4: in contrast to cities linked via the infrastructure predating the Arab conquest (roman roads), cities outside this network, and linked via caravan routes instead, are larger than the other cities, pointing to a clear discontinuity in the urban system following the Arab conquest: camels have taken over the role of horse-drawn carts

The footnote for the last paragraph above even states that one of its sources claims that wheeled transport disappeared (I guess that must be a huge overstatement) and also attempts to give an explanation for this change:

Hourani 2002: 44: ‘In the greater part of the Near East wheeled transport disappeared after the rise of the Muslim Empire, not to come back until the nineteenth century, and various reasons have been suggested for this: Roman roads decayed, the new Arab ruling groups had an interest in the rearing of camels, and transport on camel-back was more economical than by cart’; according to Glick 1979: 24 the disappearance of wheeled transport antedated the Arabic expansion by several centuries, but he also stresses the link with the military use of the camel.

In its concluding remarks, the paper says that although the Muslim world was quite innovative in adopting the caravan routes as the preferred method of transport for trade, it ended up limiting the later and larger gains made by improved maritime technologies:

Another factor that we argue has played a substantial role was the importance of different in modes of transport. In a way, the Arab world was more innovative in that it replaced the system of Roman roads by caravan routes, and the cart drawn by oxen or horses by the camel packed with goods (a rational move as camel transport was a more efficient means of transportation – there was no need for road maintenance and the camel outperforms the horse when it comes to stamina in desert type conditions). By focusing on caravan routes, Muslim cities to some extent turned their back to the seas, which initially may have been related to the fact that during the Arab Conquests of the Middle East and North Africa, Christian powers – in particular Byzantium – still dominated the Mediterranean, which made sea transport more risky than overland trade. This choice for camels and caravans as the key mode of transport had long-term consequences. Given its technology, prospects for productivity growth were meager; in fact, the productivity of camel transport may not have changed at all during the ten centuries under study (see Austen 1990).

This comment from another thread also states:

Instead, camel caravans made increasing sense, as the Islamic states that succeeded the Roman Empire streamlined government, abandoning road repair but also taxing trade less and intervening less directly into the affairs of urban families. From a broad perspective, the transition from Roman boats and wagons to Arab camel caravans on the 'inland sea' of the deserts demanded the careful maintenance of bridges and the construction of caravanserais (inns built around courtyards at watering holes across the desert).

So, how much of this is accurate?

And if it is, why did the Muslim world largely relinquish the old Roman systems of transport to second place?

Was it a conscious decision or the conclusion of a trend that had already been going on for some time (e.g. socioeconomic benefits or environmental conditions such as desertification)?

Finally, what was the state of all these transport methods during the Ottoman Empire, after it had conquered the whole Eastern Mediterranean? I know that they maintained a strong naval hegemony at least until the Battle of Lepanto, but what about trade?

EDIT: also posted on r/history