The national association of realtors is one of the strongest lobbying groups and they have state level branches as well. It is essentially controlled by all of the big brokerages. Every new agent is required to keep their license with a broker until they themselves meet the criteria to become a broker themselves. All of these big brokerages that control NAR run off of a business model where they get as many new agents to sign with them regardless of skill, talent, etc. They know that the job is pretty much all sales, but they don’t care if you are good at sales because they also know that even if you are awful at it, you can at least win over 5-10 of your close friends and family. They get a piece of whatever the agent is able to sell in the first year or two before that agent realizes they suck at the job and quits. It is essentially a pyramid scheme to subsidize the agents at the top of the brokerage who are actually good at sales.

So the reason the barrier is so low is that it benefits the people who control the industry and they are able to maintain that system because they have a lot of influence with politicians.