There are also other costs, other than only transmission losses. If you're crossing multiple countries (which would be the case in such a long cable), there nee

There are also other costs, other than only transmission losses. If you're crossing multiple countries (which would be the case in such a long cable), there needs to be a clear path for the cable to take(ie. pay people to use their land to put a power line on), multiple legal jurisdictions, a higher rate of failure because of the increased cable length, more maintenance, etc. From speaking with an EE friend of mine, he mentioned that for long distances, DC is more appropriate and most of my (limited) knowledge revolves around AC. So it might technically be feasible, even though it would be politically hard to do so.