guess by your non answer, you don't work in the marine industry so you are guessing that safety is not a priority
if you had worked in the industry you would know that all officers on ships either engineering side or deck side have to be licensed and are held to an international standard
those licenses take as long as 10 years to complete depending on the level to be obtained. master mariner or chief engineer are the two senior most certifications. these officers have log books regarding their historical employment
it is possible but highly unlikely that most mariners who were educated in the western world would risk their license over profits for a company and they are protected by international law to operate as they see fit as well as being pressured by unions to observe safety
while accidents do happen and companies do try and cut corners, it is not quite as corrupt an industry as you (presumably a landlubber) make it out to be. safety corners don't get cut like they used to because the punishment for infractions involves going after corporate individuals as well as the companies themselves.
the marine industry will put a chairman, ceo, superintendent, master mariner, engineer, in jail as well as a hefty personal fine for deliberate violations of safety standards.
when I said, it used to be but not very much anymore, these penalty changes are the reasons. fines can be over $1million but it is the jail time which has most corporate entities as well as senior mariners worried
when a new mariner gets signed on a new ship, in most cases the master or chief with give a hefty lecture regarding safety so there will not be any carelessness contributions or lack of safety attitudes
far cry from the old days
You should read some NTSB/USCG reports on vessel collisions/losses - all fully licensed Master/mariners/engineers, driving a ship in poor condition, with unknown status of cargo (was everything properly secured?), into extremis. Unfortunately, hands-off approaches by companies, drives for profits, and poor leadership/culture shipboard and in the company all contribute to civilian maritime disasters (and numerous close calls).
Over time, shipboard manning has gone down. A super-tanker can sail with like 15 people on a 400,000t vessel. That's just crazy... Reduced manning (which is argued to be OK due to automation and IS OK...as long as nothing breaks!) brings the crew closer to suffering the effects of fatigue (less backup from your equally-tired shipmate). Law requires a person stationed as lookout at all times, but its well known by folks at-sea that ships don't always do that, or the guy on the bridge is asleep, or in this case perhaps, a language difficulty (Chinese crew talking with Iranian crew, I believe) results in misunderstanding.
Earlier comments are germane - these ships are very slow to respond (unlike cars), only operate in one plane (unlike planes, pardon the pun!) and one can easily lock onto something else of concern and miss the (seemingly obvious) threat elsewhere; even seasoned mariners fall prey to this, especially if fatigued. This is what happened on USS FITZGERALD (another good read, from the USN) and happens in many maritime accidents. Radars can also miss things, lights can be confusing (they shouldn't be, but if the ships are close to shore with cities in the background, its ridiculously hard to differentiate what you see on the screen with what's on the water), mechanical malfunctions can occur at the worst moment, all these things can compound to result in this type of disaster.
I've no doubt safety culture, as a whole, has risen over time. But not in all companies and not on all ships - keeping a strong safety culture and ship (or similarly complex piece of gear) in good condition is like balancing on the tip of a bamboo pole in a windstorm - takes lots of focus, attention, energy, and commitment. USCG found quite a few ships terribly out-of-code a few years ago - they're required to be in-code by ABS (or similar) and USCG, they all know this, but the companies and crew allowed it to happen.