For extra context: that "3× deeper" makes costs seriously explode. People do know how to engineer for that depth, but it's a lot of effort and there's pretty much no commercial market. For shallower stuff there's oil rigs, deep-sea cables, seafloor mining, even just tourism… but at some point it just peters out and only research vessels tackle the depth.
(source: friend of mine works at a UK university doing deep-sea vehicles)
For extra context: that "3× deeper" makes costs seriously explode. People do know how to engineer for that depth, but it's a lot of effort and there's pretty much no commercial market. For shallower stuff there's oil rigs, deep-sea cables, seafloor mining, even just tourism… but at some point it just peters out and only research vessels tackle the depth.
(source: friend of mine works at a UK university doing deep-sea vehicles)