From a pure immediate money perspective, sure changing immediately to a higher paying job makes sense.

However, generally each new job comes with a ramp up time before you become useful and then a further ramp up before you can develop new skills (in my limited experience).

I don’t think I could properly progress in my career by building higher level skills if I had to learn new organisational practices and technical skills every few months. And arguably, IMO proper progress is essential to securing significantly higher salaries in the future (but I’m not sure how the total money aspect works out though).

That's a fair point but to me that's already built in to job hopping. If you're not able to secure a new job (or hold down an existing job), then you keep progressing, but at a higher salary. I work for money and nothing else (I couldn't care less about software) so I gain no benefit from doing the same thing (growing my skills) at a current job than at a new job with a much higher salary.

> why stay at company A

It obviously isn't a universal preference, but I get most of my job satisfaction from having deep familiarity with the ecosystem I work with. I don't get that level of familiarity before a year or two, and it only gets stronger from there. I'm about to hit 4 years at my current job and my job satisfaction has never been higher. I might be able to make more money by hopping to a FAANG, but I would surely take a hit to my happiness.