A real estate license mostly teaches what you need to know about the laws around real estate transactions. It's pretty easy to get. Take the courses, pass the test, and you're in, there's no restricted access. You can set up your own brokerage and everything.
But if you want your brokerage to have access to the MLS system, you have to join the Realtor organization. That's where the monopolistic behavior creeps in.
Your location may be different, but what you are describing is not universal or even common in my experience working in multiple states. Yes, it is absolutely true that there should be a higher barrier to entry and even after "first renewal" (which is normally a second round of education), there isn't enough training before we let new agents loose into the world. That said - in every state I'm aware of, you work under a licensed broker who has additional licensing, training, and legal responsibility. Until you've reached that level of licensing it is not possible to set up your own brokerage. I've seen a work around where a non-licensed business owner paid someone to be their broker, but that regardless there has to be someone with the right licensing running the business.
Also - whether MLS members must also be Realtors is a rule of the MLS and not a universal requirement. The NAR, nor MLSs, do not set commissions. In fact, much of the MLS rule changes in recent years that I've observed have been about making sure non-Realtor licensees have market access. It's right there in our paperwork that I show clients where we ask permission so that the seller knows who will be entering their home.
Most states require some years of experience before you can become an independent broker, in Florida it's 2 years of active work / 5 years in the system.
But if you want your brokerage to have access to the MLS system, you have to join the Realtor organization. That's where the monopolistic behavior creeps in.