Let me counter with a couple thoughts. Agreed it is quite easy to find a comfort zone with organic traffic. You speak of that quite well.
With respect however, your post sounds like something I would read on the official Google webmaster forums. Those that understand that mentality there would applaud your sediment.
You're essentially saying you sucked some person into buying your site. Correct? No guilt there eh. You didn't want to let them know about free traffic and Panda and the fact that Google could dry up the organic traffic on them. Sucker beware! I would feel different about your post if you had of left out the part where you sold your site to some sucker. Karma please? I wouldn't be posting about it that's for sure especially when if I'm telling people they should know better. Either that or you are NOT psychic.
You know what the internet is? It's a stock market. If you have a website you depend on the stock market. Guess who own 80 or 90% of the stock market? And you're suggesting there are alternative? Like there is some other stock market out there? You are along for the ride when there is one company on the stock market.
You know what though? If Google chooses to spike what you pay for Adwords then what? The fact is, whether it's free traffic or if it's ads, you can still be screwed. If you have a tight budget and Adwords is the only real traffic solution, and Google decided to make you pay extreme amounts of money, then what? It's the same thing. Foolish us for investing our hopes in the only company on the stock market.
I will close with the fact that Google has 97% of mobile search. Think about next year and the year after that in terms of people using mobile search. To say that you can create a successful website that doesn't depend on Google is with respect, a joke to me. Some people win the lottery and some of them post here. Congrats.