As cknoettg said, IT is very broad. You can go from answering phones on a Help Desk to managing databases, and a whole lot in between. I do level 2 support, desk side, the people who come to your desk to fix your problem. However there is a lot more to the job. I'm currently making about $65K plus over time and on call. But, I've been doing this for over 20 years. I'm also working at a non-profit.
You can make over $100K in a lot of the other IT areas, but you can't start there without certifications and a degree.
IT work can be as easy or difficult as you want to deal with. The easier it is, the less it pays. Though as one person pointed out to me, things that are easy for me, may not be easy for someone else.
As far as being replaced by AI, not going to happen for most IT worker roles any time in the near future. There may be some things that AI can be used for, but AI doesn't handle the unexpected very well and IT is full of the unexpected.
As far as being in demand there are very few companies that don't have computers in one form or another. I've worked in banking, manufacturing, government, health care, and other industries. They all have computers to help them get the job done.