it might actually help the Romans as they had an enormous trade deficit whit china so if they trade less they might actually have more money which could be used in the empire or the Romans just spend more resources to beat Persia to get a better deal
It was most certainly not a negative... The conception of trade deficit does not matter in actuality; the real benefit of the Silk Road at its height, is that it was implicitly weakening the Arsacids.
@Gloss Rome did circumvent the decline of the Silk Road beginning in 240 CE, with the Indian Ocean trade. Within the Islamic period, the need for this trade was removed through conquests and looting. Within which, there was a creation of an inter Islamic trade transit by land.
@Eanur The Arsacids could not ‘block’ the Silk Road. To do so, would require a greater militarization of the Arsacid-Kushan borders, which was not possible as the Arsacid would be invaded surely from east and west had they postured against both of their neighbors at once (Rome and Kushans). Arsacid economics likely also benefitted from this trade overland from China and Hindustan, to block its route westward, would damage relations with the Kushan and their internal merchants and nobility, who would side with the Kushan and bring ruin to the Arsacid royalty.
In the Sassanid era, this weakness of the Arsacid on both of its major borders, was solved. Namely, the Sassanid imperial forces crushed Rome in Armenia and along the Euphrates and devastated Emperor Vasudeva I of the Kushans, conquered the entirety of the Kushan empire outside of Hindustan. While this made Eranshahr far more powerful, it certainly fueled even further the deep decline of the Silk Road. Already China had become much less the power it once was and the loss of the Kushan, meant that the connection between Hindustan, China, Mediterranean, etc had been replaced by a hegemonic Sassanid empire. This hegemony of the Sassanid eastern realms, though unlike the Kushans, did not promote the same level of inland transit, hence the slow decline of the Silk Road. By the 5th century, this would become further apparent with the return of dominant steppe hordes that warred with sedentary populations and caused chaos across transit links, such as the Rouran, Huns-Hepthalites-Huna, Celestial Turks, etc etc...