Interesting rant! Here's my response to you: Yes credit card companies make obsurd amounts of money off of interest, but that's where buyer responsibility comes into play. A person should not be spending more then they have, and people don't necissariy use credit cards just because they don't have the funds available. Alot of people are after the rewards, as well as improving thier score to get a lower interest rate on a car, house, etc. Allthough it is not the smartest, I respect your decision to quit the credit "monopoly" game. Since you plan on paying cash for everything from now on, simply having a credit card and buying a single coffee a month, or using it for any small purchase would easily boost your score. For some people they feel the need to moniter their credit closely which is why they pay monthly for it. If it's not that big of a deal to you, like I said before, nobody is forcing you to pay for the monthly subscription. I hope I helped shed some light on the fallacy of your idea. Unfortunatley it's just going to hurt you in the end when you wind up paying a rediculous amount of money for a mortgage or when you can't buy that nice new car because you don't have sufficient credit. BUT, if you plan on spending the rest of your life paying in full with cash then so be it and I wish you the best of luck 
Speaking as a consumer: FICO scores are simply the risk that you're going to flake on an extension of credit.
There's nothing really magic or instrinsic about it; yes I agree some of the policies the CRA's have and how things are scored are laughably stupid, but that's starting to change with more recent models... now we just have to yank some lenders (I'm looking at you Fannie and Freddie with that EX Risk Model V2 score you underwrite on) into the current millenium.
I lived a cash-based existence until I was nearly 36 years of age: no problem, here's N x yuppie food stamps to solve the issue. Until I got face to face with California housing prices, and I can't cough up $750k in cash for a house in a good school district. So, building credit... and my expenses haven't changed one bit by using credit cards, and only slightly (marginal interest) on financing a car instead of writing a check.
It's a means to an end and the information on how to optimize a report is readily available for free here and elsewhere; I agree it's a game we possibly shouldn't have to play as rigorously as we do, but that's the modern financial system. If you prefer something other than the American financial system, there are places that can be accomodated... just credit scores are a fact of life here and in most Western societies. If you have hard currency some of those places would be happy to take you too; however, unfortunately end of the day there's no utopia at least here and now for humanity, and there's tradeoffs whatever society you live in.
If you want to be successful, just make the credit system work for you instead of against you. It's not difficult, just takes some time to get to gold plated status but literally anyone can do it. Why not simply do it and take the money when you need it?
OP: You did not say what your credit scores are. Everyone has their own definition of "plummet" and frankly, from the number of accounts you say you've paid off, it would seem you already should have a reasonable score.
Please share more about your specific credit profile components, and where you are finding your FICO scores, and what those scores are.
Sorry to hear you are frustrated, but it's not personal, it's just the way this economy works in an impersonal way. You can participate or not, but there's not much to do about the system as it has evolved to this point, except do what you can to understand how it works, take advantage in areas that you choose where it can benefit you.
Good luck!
