My company has struggled with this too. We’ve lost all the Zs we’ve hired within the first few months, and we were deliberately trying to mentor them so they could gain the professional skills they were very clearly lacking on hiring. I invested so much of my time training them on how to write an email, how to write a document using complete sentences, how to proofread a document, and how to be in a meeting (4 different Zers individually, who could not do any of these things without significant hand-holding).

Once we were happy that they were up to speed and on the same level as the rest of the team, they left. Consistently their reason was “thank you for giving me the skills I needed to get a better job.” Which, great! I guess. But that leaves me pretty stumped. How am I supposed to train new team members knowing that they’ll leave at the first opportunity? I’m not a manager, so it’s not really my problem, but ya, it’s frustrating for this elder millennial who just appreciates having a job that isn’t exploitative.

Treat them as normal understand them listen to them you should be good

I think, like others have said, an exit interview is your best bet if you really want to know.

We don't know anything about what it's like to work for you, what you do, what everyone gets paid, etc. Tell them you want to know and they will most likely be happy to tell you.

I'm on that brink between the two. My experience is that people are less likely to deal with inconveniences, especially during the ramp up period. There is a sense of immediacy that has been growing in recent years on all sides of work. Some people will feel as though demand on them increases disproportionately to the time and training provided them.

My parents always advised me to "Wait it out" if I didn't feel comfortable or prepared to do the tasks a job required of me. However, while most places are slow to fire someone for not being up to task, there will be a good amount of pressure and expectations to succeed. Every job I've had, I could do the work, but didn't know their proprietary systems or unique business processes in use. So while I interviewed well, I struggled to demonstrate my skills because of a ticketing system or set of forms required. Nobody was too friendly to someone who said they were good, but can't hit the ground running.

Keep in mind, as others have said, that most younger people are only just now entering the workforce. They don't know how to work, they don't know what's normal, they don't know what to do or what to expect. They're seeking a place where they can get guidance on how to be productive. Not in terms of micromanagement, but in terms of adequate instruction, offering of support if needed, and empowering them and providing them resources needed to succeed. If they aren't comfortable, don't feel the right vibe from the workplace culture, can't figure something out... the patience for such things is very very thin. Not to say you should walk on eggshells, but as also said: they don't have loyalty yet. Most young people see it as a necessary evil to work, and most companies something to tolerate, not embrace. They will bounce at a moments notice because they aren't married to the concept of being a "company person".

It's a difference in how their work ethic is applied. They need that immediate return for their input. There is no safety in working towards something several years in the future if the future doesn't exist, or won't be kind to them. So they seek more benefits that are applicable to their daily/weekly life. I know you mentioned Europe, so they don't face the American problem of being fired at will or layed off with no notice. But it is something to consider that there is seemingly no perceived value to staying at one place until you retire like was had in the past.

~ Just some thoughts.

Are responsibilities being spread fairly or are older employees dumping the shitty work onto younger employees? Does the workplace unfairly reward employees based on how long they've worked there? I've worked in those environments and it sucks.

This reminds me of what a relative told us about one of their first days at work. Some HR manager apparently told them that he wishes for everyone present to get into the situation where they'd leave the company at some point. He admitted that he probably shouldn't say something like that as HR person but they're all still young and it's a good thing to broaden their experience and see other companies/company cultures etc.

Furthermore, when seeing memes and other posts about things like the housing market I'm not surprised that lots of people steer away from being loyal to a company and towards making more money (though that doesn't seem to be the case here based on what I saw from other comments)