Unless they need to be prescribed in ratios that can't be achieved reasonably with the cheap OTC pill dose sizes, it's not clear to my why I'd want a combined bill instead of just taking separate pills.

Taking more than one pill is less convenient, but except for people who have trouble with pills in general I doubt they would want to pay more for that convenience.

Even in the case of fairly high doses, it is not too bad. A few months ago, for example, I somehow managed to get a painful rotator cuff injury while sleeping (no idea how), and my doctor told me to take 1000 mg Tylenol every 8 hours and 800 mg of ibuprofen every 8 hours. At the most common OTC strengths, that would be two Tylenol pills and 4 ibuprofen pills.

It's a damn shame that doctors often fail to tell people about cheaper and more irritating alternatives, but there's nothing wrong with giving people the option to pay more for a better experience.

You often see this in terms of number of times a drug had to be taken per day. There'll be a generic that needs to be taken say three times a day, and a newer drug that only needs to be taken once.

I highly doubt every manufacturer of Ibuprofen or Acetaminophen would decide to throw in the towel if this new drug was released.