Of course, the popularity of acetaminophen was generated by an aspirin scare designed to panic people away from that previous holder of the "most commonly used and effective pain remedy available in the world" title. An association between aspirin use in children and the extremely rare Reyes Syndrome (but no causation finding, and plenty of Reyes Syndrome cases occur without aspirin use) was used to bring aspirin use for children to a grinding halt, with people being encouraged to give acetaminophen infants and toddlers, who would have been infinitely safer taking a baby aspirin. Peddlers of branded acetaminophen products milked the scare for all it was worth, touting their products as "safe" in ads aimed at adult usage.
And the definition of "children" got stretched further than the Brady Bunchers ever stretched it in their "children killed by guns" claims. As a 24-year-old college student at the height of the Reyes-aspirin hysteria, I was informed by my college's health clinic that they couldn't give me an aspirin because they didn't stock aspirin anymore "because of the risk of Reyes Syndrome". The facts that 1) Reyes Syndrome was exceedingly rare to begin with, 2) over 90% of cases were in people under age 15 (and most in much younger children) and about 10% of those in children who hadn't taken aspirin, and 3) it ONLY occurs in conjunction with a symptomatic viral infection such as flu or chicken pox, were all irrelevant. College students with sprained ankles or menstrual cramps had to protected from aspirin, so they were showered with acetaminophen instead.
All the NSAIDs have the commonality of producing gastrointestinal upset that can lead to bleeding ulcers with prolonged use. Acetaminophen is usually lumped into the NSAID discussion but does not produce this gastrointestinal upset and actually, one of the indications for the use of acetaminophen is to treat gastritis.
The most common affliction of people taking NSAIDs is the irritable bowel syndrome or acid reflux -- which is the fastest growing treatment modality of the Baby Boom generation. If most of those people would switch to acetaminophen, the incidence of gastrointestinal upset virtually disappears -- because tht is not one of its notable side effects.
The creator of the guaifenesin protocol for the treatment of fibromyalgia has noted widespread adverse reactions to aspirin -- but thinks it only happens with those who have fibromyalgia rather than it is much more universal in the general population.
For many years I had increasing irritable bowel symptoms after using NSAIDs for childhood arthritis, until after bleeding internally, I decided I had nothing to lose by seeing if acetaminophen would work. The pains are as well controlled and there is no gastrointestinal upset -- which I thought was an inevitable aging effect.
The liver damage has been mostly noted in those deliberately trying to commit suicide by the use of acetaminophen with alcohol. Other than that, its superior safety record accounts for the majority of baby pain relievers being acetaminophen rather than aspirin.