A broker will usually sell the thing that makes them the most money, if what they sell might be a reasonable solution for the customer. Of course either or any Medicare decision can be considered "reasonable". But there is absolutely no doubt in my mind that the business model where there's a profit-driven business between me and medical services is not "optimal".
The Medicare Advantage plans are VERY complicated. The book they give you is over 100 pages, and that's a summary of the plan! You can't even get a copy of the actual plan document, or at least I couldn't wrangle one. Those documents are on the order of 750 pages. I got the impression you did your research. Did you analyze either of these documents? Were they easy to understand?
This seems analogous to the variable annuity vs spia, for the investment geeks in the audience. The variable annuity must be "sold" by a broker, who makes a ton of money on the sale.... nobody just buys one. The rules for a variable annuity are long, complicated, and nearly impossible to understand. Contrast that with a fixed annuity, which people seek out and buy, and commissions are minimal. Sounds a lot like the contrast between Medicare Advantage and Traditional Medicare.