I mentioned management from other professions. I have people that I went to school with that are earning close on 50% more as they have moved in to management in their respective fields. Auditing, financial management etc.
You shouldn't be comparing yourself to others based on salary and position, you will ALWAYS end up being disappointed and demotivated, even more so when comparing to people in other industries.
Like others have mentioned, 4.5yrs is really minimal in terms of experience and you are earning a v good salary for that amount of XP. I think you need to decide on which path you want to take, do you want to go the managerial route? Do you want to become a guru in development? You could also look into becoming a systems architect, business analyst etc.
I.T is definitely not flat (Unless the company you work for strictly keeps you at certain level).
As a coder, what about looking at security? Do some free ethical hacking courses, penetration testing etc. With POPI coming into affect very soon, client data security/privacy is MASSIVE, get into one of the consulting firms who are outsourced by financial companies and you're in a whole different world.
Just some food for thought.