To address your specific points, and as someone who's done a lot of hiring for different companies over the years:
- Yes, lots of job hopping can be viewed negatively (please see below).
- I've been amazed by the number of people I know who've changed jobs mid-pandemic. Clearly there is still a job market out there. With that being said my default position agrees with yours: unless you have a very compelling reason to change jobs, if your current job is secure, stick with it.
Back to job hopping...
If you've been working for 10+ years and never held down a job for more than a year or two the alarm bells start ringing. If you've pulled that off for 15 - 20 years all of the alarm bells go into maximum overdrive.
However, I certainly don't mind a bit of job hopping early in your career: it can take a while for people to find a position that really suits them.
Similarly, peoples' circumstances change: they get married, they move, they have children, they're made redundant, they have health problems, they need to care for a relative, they suffer bereavement, or they just get bored and need a change and it takes a while to figure out - not to mention all of the other changes that can happen within a company that make them to look for work elsewhere. The result is that people might go through another period where they change jobs more often: they might start contracting, or if they move and have to change jobs the first job they land might not be that great.
Often I've seen on CVs where people have been with a company for a long time, then might change two or three times after that because really good jobs that suit you well aren't actually as common as we'd all probably like. Again, that's generally OK.
What I do want to see is some solid evidence that under the right circumstances you can hold a job down and stick at it for a few years. The amount of evidence I'll want to see of that increases proportionally to the length of your career.
This is an inexact rule of thumb. Changing jobs a lot may not immediately put me off a candidate but it will, at the very least, mean I dig into the issue very thoroughly during the selection process, and if I don't like what I find then obviously you won't get the job (but that's true of any aspect of selection).
With that said it is possible to stay in a job too long. I was with one company for 10 years, and that was too long. Far too long. But not because it was 10 years: the company had stopped growing at the time and I'd run out of opportunities to really develop and advance in my career. I'd say I wasted at least the last 3 years there. In terms of career advancement that 3 years has probably cost me more like 5 - 7, because I was burned out and pissed off, so I spent a couple of years contracting before moving back into full time employment.