The copays are not usually that big a deal. If there’s a $25 copay to see a doctor or a $10 copay to get a prescription, that might put some people off, but what’s more important are the deductibles and limits and other fine print.
You may go in expecting to pay your $25 copay but end up with an $8000 bill, and since your insurance has an $8000 deductible, they won’t pay any of it. If that happens in December and you have to go back for a followup in January, expecting another $25 copay, you could get another $8000 bill because it’s a new year and the deductible has reset. Now you’re $16,000 in debt even with your good insurance with the manageable $25 copay.
Then say you get another bill, maybe $10,000 for a dose of tylenol and the paper cup they handed it to you in or something ridiculous like that. But your insurance company has a limit on how much total they have to pay out for that thing, so you’re stuck with the bill. And all the while, you’re still paying 15-30% of your income or so to the insurance company. Only now you’re sick, so you have to take leave from your job and therefore lose your insurance…
It’s an industry designed in detail to prey on people continually and drop them in their time of greatest need.