You can tell me that the new law and its various provisions do not affect existing plans until the end of time, what you cannot tell me is that existing plans will exist because I can demonstrate that not everyone will be able to keep their plans.
nHealth existed for two years and over those two years lost $10.6 million, cumulative, never once showing a profit. Start-ups fail, the reform law isn't going to change that. Other businesses fail, too, and you're right that employees won't be keeping their coverage if their employer goes out of business (that's a good reason to decouple health insurance from employment). "You can keep you coverage" isn't an absolute, Obama himself
acknowledged that it simply means the government will never force you to change it:
“When I say if you have your plan and you like it,…or you have a doctor and you like your doctor, that you don't have to change plans, what I'm saying is the government is not going to make you change plans under health reform,” the President said.
Perhaps you interpret "you can keep your doctor" to mean that reform will prevent your doctor from dying or retiring as long as you like him. After all, if he reaches retirement age or dies unexpectedly that must indicate someone lied to you, right? I mean, you can't keep your doctor if he dies. Nor can you keep your insurer if it's a small start-up in a volatile market and dies.
Obviously some people won't be able to keep their coverage when their employer switches plans, etc. That's always been the case and it isn't a particularly uncommon occurrence. The point is that giving up your plan isn't a requirement of the law, it's the prerogative of you and your employer, it's the mercy of the insurance market, it's a dozen other forces that affect which plans are available to you.
I doubt you could identify a single one week period in the last 50 years in which everyone in the country retained their insurance plans and no one switched. People lose and change (not always voluntarily) their plans constantly. You seem to think someone is pulling the wool over your eyes by not stressing this point again and again when in reality it's so basic and commonplace a fact that it's just sort of assumed this is acknowledged. Churning will never stop (if it did there wouldn't be a market for insurance, there would be a static situation where no one ever buys it).