I’ve spent significant time training and mentoring new people. Any time they ask me something I’ll drop everything to help them, as I don’t want them to think I’m ever too busy for them. My default is assuming someone is going to stick around, unless their words or actions tell me otherwise.
I will agree that companies can and should do more to retain people if they want people to stick around. For instance, when I started there was a pension, which no longer exists. They also made it clear during the hiring process that they like people who stick around, though I don’t get that vibe anymore.
At the same time, new hires need to be realistic. Some of them hired in and claimed to be experts, knowing everything there is to know about the job they were doing, in about 6 months, and started asked about promotions. First, promotions are reviewed annually, so expecting one after 6 months wasn’t realistic. Second, thinking they knew everything showed just how little they knew. They were still constantly asking for help and had large gaps, but instead of worrying about getting better to earn the promotion, they felt entitled to it after a very short period. I did the job they were doing, at some level, for about 6 years and there was still a ton of stuff I didn’t know (and still don’t)… and I wrote 90% of the documentation, procedures, and training material. I’ve only seen 1 or 2 people be reasonably self-sufficient in less than a year, and those people were never arrogant about it the way many others were, they still recognized there is always more to learn.
While I might have been able to make more early in my career if I job hopped, I think I would have capped out at a lower level, as my biggest and most frequent promotions came during a period where my knowledge of the internals of the company were of a lot of value. That isn’t something that can be hired; it takes time.
Imo, only similar type of people get the attention which they can usually use better at another company making more but sucks for the senior. Hence, mentoring should be done selflessly based on who needs it most as it ends up increasing the average and hopefully some other senior somewhere trains your new hire.