OK, you ask for Medigap disadvantages. The whole Medigap theory is a reactive approach. My MA is a proactive approach. My MA has preventative things. So this is a big disadvantage of Medigap. I can give a whole bunch of examples of how they try to get/keep you healthy, if you want.
A second advantage of my MA is the speed at which they process claims. My MA is within a few days. DW's Medigap is lengthy. A recent misbilling took her two months to clear up.
I have more but I will address the "However if you get sick, that disadvantage can disappear very quick." Yes, my MA has co-pays, but no deductibles and no premiums. In some years, you will do better with an MA and some years you will do better with a Medigap. This is the whole concept of risk management. Do want to pay nice regular premiums or only pay when you are sick? Personal choice. Let me ask you this: For your house, would rather pay low premiums but have a higher deductible or pay high premiums and have a low deductible? Again, personal choice. But I hear from people are passionate that a high deductible on a house is bad, stupid, etc.
On my MA plan, if I save $2,000 per year for a number of years, but have a number of years where I pay more, is that bad?
I don't understand this point: "Another point, clearly the dollars allocated to Advantage plans is to high." I think you are saying that it costs the government too much and is therefore bankrupting Medicare. Is that correct?
Your last point is: "The are spending on advertising with thousands of commercials to coerce you into a plan. If it wasn't overly profitable they wouldn't spend so much pushing it." I think you are saying that the massive amount of spending on advertising proves it is too profitable and therefore their product must be bad. I don't see that one follows the other. I could argue that all advertisers must be bad by that logic, but you would say that I was offering a strawman's argument. I could say that they have to advertise to overcome all the negative things about MA, but you would say they are doing a bad job as we are all sick of Joe Namath and JJ Walker. I will just agree that we are all sick of the MA advertisements.