If your next hire is only going to stay for 1-2 years, it doesn’t make sense to hire a junior team member and invest in their growth.
As a job hopper myself, I can’t fault others for doing it though. I never hopped for the money. I just got bored or felt isolated in my role. But a nice consequence is that my salary actually appreciably increased, as opposed to colleagues/friends who stuck with the same company.
I think anything less than that, and you haven't had time to really learn an ecosystem, and more importantly you might not have had a chance to live with the consequences of your technical decisions (i.e. supporting something in prod that you built).
I know plenty of people who started somewhere, left for a while, and then came back and ended up in a position higher than they would have gotten if they had stayed put and tried to climb internally.
And yes agreed that moving around will 100% grow your comp faster than staying put (in most cases).
Like right now I've been at current co for 3 years. At the start I was getting decent raises after big projects. I now have increasingly more responsibility, I'm doing hiring, I'm doing mentorship, I'm doing huge feature work, I have to waste half my time talking to the braindead stakeholders. And what do I get for that? Absolutely jackshit, I'm getting paid the same I was when I had a quarter of the responsibility and work, yet the company is boasting about making ever more money as they lay off entire teams of people.
Why on earth would I be loyal at this point, it's clear they don't give the slightest inkling of a shit about me or anyone else who does have "Head of" or "Chief" prepended to their title.
You get what you optimize for, really.