The linked site provides the following assessment of efforts to find the ARA SAN JUAN prior to its discovery by the US company OCEAN INFINITY on 16 Nov 2018, 366 days after it was lost:

"Balbi went on to indicate that the area where the SAN JUAN was found had already been combed before – five times, according to Infobae – but argued that no one had been able to locate it because they did not have the adequate technology, which Ocean Infinity did have."