Change isn't necessarily positive, and that's where most people (including myself) chicken out. For instance, leaving my current job, in which I've been working for the past two years, looks like a huge leap to me. I know, that I'm going to get paid each month, with an above average salary, how to manage the job and what to expect from it. However, I'm positive that I've missed a handful of opportunities by staying stagnant.
It's basically being scared to lose what you already have, moving out of your comfort zone is a copious procedure, not many take such risks.
I was fearing the same thing, I wasn't promoted to higher level in my job for 2.5 years, most anyone has ever worked in that position at my last job was 8 months, I stayed there for 2.5 years, I broke the record and then near quadrupled it, so I was a great employee and they didn't allow me to switch departments in the same place neither stating I am crucial for the work.
However they didn't give me any chief position, didn't promoted to higher level and so forth. Basically, it is not going to be anything good for me there as long as I stayed, so I quit and ever since then I have been a lot better. But I had friends like that who ended up a lot worse, like for example my wife was a teacher and she always wanted to be a teacher while growing up but after she became a teacher during her 4th year she decided she doesn't want to be a teacher anymore and hated her job, cried while going to work she hated THAT much.
So, she quit and ever since then she has been looking for some work that she could do and failed to do so for 3+ years now. So, I would say it is really not all the same and I get the idea of how quitting your job could be scary but if we don't do it then we can't grow and never have a "chance" to fill out the maximum our life could provide us.
I'm stuck in a job I do not like, while I have recently graduated from university, however, the money is quite decent and at the same time, it's a pretty stable job, one day off per week and two paid leaves per month. I've known the manager for two years now, he isn't the worst, but I've learned how to handle him and usually, my requirements (regarding work schedule) are met.
Despite not liking the job, I still haven't abandoned it. I've graduated, and I'm still there, I haven't even looked to find somewhere else, until a few weeks earlier. I'm basically stuck in a loop just because I'm too stagnant to get out of my comfort zone and try something else, mainly because I'm afraid that this something else, could be worse than my current situation.