What makes ibuprofen dangerous is that people tend to believe it can be taken safely to address arbitrary aches and pains. However, the kind of people experiencing aches and pains (beyond a common headache) tend to already be on some other form of medication. More often than not, these medications are either NSAIDs or steroids. Both of which interact poorly with ibuprofen, given that it is itself an NSAID. Paracetamol does not suffer from this issue.
I know little of how THC and CBD interact with other drugs people are likely to be consuming. However, drug interaction would need to be taken into consideration. As would subtle effects on mental state; focus, lethargy etc.
Prescriptions are for things that are dangerous under casual misuse, not intentional suicide or ignorant children.
Paracetamol is not an NSAID (unlike ibuprofen) and has a lot less negative effect on my gastritis. There are not many painkillers available OTC which are not also NSAIDs and so don't destroy your stomach lining. I'd rather not develop stomach ulcers to prevent some random lunatic from gorging himself on paracetamol into the grave.
At the same supermarket, AUD 3.10 (USD 2.19) buys 2 packets of 24 tablet 200mg ibuprofen. Swallow 48 tablets, take a 9.6 gram overdose. For a person who weighs 80kg, that's 120 mg/kg. [1] reports that level of ibuprofen overdose is likely to produce mild CNS and GI symptoms. Fatalities have occurred with >300 mg/kg, so an 80 kg person would need to take over 24 grams, which is 120 tablets, 5 packets worth (cost AUD 7.75, USD 5.48). So you can immediately see how ibuprofen is safer than paracetamol, in that you have to swallow a lot more tablets to take a potentially fatal overdose. Given that, I think a case could be made for withdrawing over-the-counter paracetamol while continuing to allow over-the-counter ibuprofen.
Cannabinoids such as THC and CBD also provide pain relief, and certainly if we are just looking at overdose acute toxicity are far safer than either ibuprofen and paracetamol – indeed, there is no record of any fatal overdose ever happening from either. And yet, where I live they are only legally available on prescription, and prescribers face regulatory hurdles which do not apply to other drugs. If we are only thinking about safety in overdose, we'd make both ibuprofen and paracetamol prescription only, and allow THC and CBD over-the-counter instead.
[1] https://litfl.com/nsaids-toxicity/