I've been on modern sailships as well, and also read a bit about 17th and 18th century ships. My impressions are that (excluding galleys) life conditions on board had to be "good enough" and sailors (and soldiers) would openly complain when the small privileges of their category were not upheld, like bigger rations for gunners, alcohol distribution etc.

On a sailship where everything is ruled and organized, you can be okay with very little comfort. Of course modern ships are much better in terms of facilities (the privy's not much different sometimes but there are showers, clean bedding, better food - sometimes - etc), but a hammock with a rug in a room with 20 to 100 other people nearby, above and below must have felt pretty much the same.

There were also vast cultural differences between nations. The Royal Navy was known for the iron discipline and punishments partly because it was very easy to recruit sailors. Nations where Navy service was voluntary, or tied to a social corps were probably different.

Today, in an enduring peace context, there is a great focus on living conditions. Though it has gotten better for enlisted men (notably because automation means more space on a ship for bathrooms, larger rooms with less people etc), some regret the living conditions on older ships with more collective life. 50-men rooms were no strange thing on some big ships in the 2000s, I guess there are still ships like that (I've never been on a ship with a crew bigger than 250). Technology (cameras, alarms, fire detectors etc) also means there is less need for watch duty both at sea and in harbour. I've been sometimes among the ones arguing officers care too much for what the enlisted crew says, especially regarding their "generational need" for social media and hourly Internet access. After a week without smartphones nobody complains about Snapchat anymore.

You're right that there is less concern for enlisted crews. I'd say the points of scrutiny are their psychological well-being (they're often new in this, so more vulnerable to depression, bullying, excesses of various kinds etc), and of course identifying potential and convincing the most talented ones to stay and progress. The reasons for this realtive lack of concern can be:

- They're young, more adventurous and adaptable.

- They have it good: the pay is generous, especially for 18-year-olds (sometimes younger) with little to no qualifications. They have a lot of opportunities, being stationed on the other side of the world, going out in strange places and harbours (except for the US Navy, you have to get two truckloads of Marines to guard the place before you can order a drink at an African bar), and get to learn the job as they progress, especially for the technical ones.

- They can leave very quickly if they want. Petty officers, CPOs and offcers are held by longer contracts, that are often very hard to break unilaterally because of legal provisions specific to the military.

- The focus is on the Petty Officers. Petty Officers have qualifications (highschool, vocational school, sometimes college), and you invest a lot in them. They learn very technical, irreplaceable skills, they manage small teams from a very young age, and you want them to stay and progress. It can take up to 20 years to make a combat management system expert, a military SATCOM specialist. You can't get experienced ones on the job market (cruise missile specialists, ship turbine experts, etc) and you're often unable to compete on salary alone (IT and data specialists, nuclear technicians etc). Not to mention you really need them on the ships...

- There are less and less enlisted crews onboard. The ships are getting more technical, meaning the bulk of the crew is made of petty officers. The US Navy counts POs in the enlisted statistics, so I don't have the exact numbers.