[1] https://news.nationalgeographic.com/news/2014/03/140326-cuvi...
https://uk.wikipedia.org/wiki/%D0%9F%D0%BB%D0%B0%D0%B2%D1%83...
The article talks about a track of holes of about 1x3m diameter. It could fit with the beak of a Berardius (or a Sperm whale?) picking things from the bottom.
Deep-water fish OTOH have been caught in the Mariana trench at down to 8000 meters. No reason why 3000 meters is the magic limit for whales.
Bottom line, they don't need the tensile strength of steel as they avoid having body parts in tension or bending (by reducing differential pressures to almost zero), they just rely on the (in)compressibility of the water-filled tissue making up their body.
Well they don't have to come to the surface every X minutes
For comparison, the human record for static apnea (holding your breath underwater but no swimming/movement) is close to 25 minutes.
some simple depth pressure calculator
a heavy duty pressure washer is about half that 2000-3000 psi. Industrial pressure washer is 3500.
The deepest-diving large, military-style submarine was the Soviet submarine K-278 Komsomolets, with a hull made of titanium, making it very expensive, but able to withstand significantly deeper dives than the best submarines made of high-grade steel, like American nuclear submarines. The Komsomolets was a nuclear powered submarine specially designed to make trips as far down as 1300 meters (4265 feet) below sea level, definitely less than the Trieste, but very significant because the Komsomolets had to "defend" a much larger air bubble against the encroaching pressure of the surrounding ocean.
Compared to the best American nuclear submarines, of the Seawolf class, Komsomolets had about 78% better diving capabilities. Seawolf submarines have an estimated crush depth of about 2400 feet (730 m). The Seawolf submarines are constructed of a high grade steel called HY-100, capable of withstanding 100 atmospheres of pressure. As a rule of thumb, the pressure increases by one atmosphere for every 10 m of descent.
http://military.wikia.com/wiki/Submarine_depth_ratings
no matter how many downvotes there are, you can't change the laws of physics away, this isn't some magical harry potter button
Submarines don't have the option of getting rid of all the air - the crew would die. Whales can exhale the air in their lungs before a dive, and the rest of their body is largely non-compressible water.
The very article you're citing even shows where your logic is failing:
> very significant because the Komsomolets had to "defend" a much larger air bubble against the encroaching pressure of the surrounding ocean
Whales have minimal or no "air bubble" to defend.