You need to figure out how to read for comprehension. Here is the entire relevant paragraph:
Aside from the problems the exchange website has been experiencing, at this point there's basically no way to evaluate a lot of the plans because many of them haven't set their reimbursement rates yet and so doctors don't even know if they'll accept those plans. So you can buy a plan (if you're lucky enough to get the website to work), but you can't actually figure out what the plan offers because the providers are unknown.
Note the highlighted parts, which include qualifiers. These make it
explicit that I'm not talking about all plans, but a subset of plans. The second sentence doesn't explicitly include those qualifiers, but since it only logically follows for the subset of plans the previous qualifiers refer to, it should be obvious to any reader with a modicum of sense that the second sentence doesn't refer to all plans either.
So I'm left wondering whether you don't have a modicum of sense, or whether you're deliberately trying to misread my post.
Almost everyone will participate? Why on earth would they?
Healthy young people are better off just paying the fine. And the point that cost is no longer dependent on health is exactly what drives the adverse selection problem.