My response to this is a bit muddled.
Simplistic statements like 'cannabis cures cancer' are daft, in fact, inhaling carbon monoxide through burning things increases your lung cancer risk, so cannabis joints, on top of just cigarettes, appear to increase your lung cancer risk.
No-one is quite clear what it is in cannabis that might have medicinal effects, or rather there's more than one thing in it and it varies between strains (CBD/THC)- it definitely could have a therapeutic effect if taken in a non-harmful way like pills or vaped. One huge problem in the UK is that it's a Schedule One drug which means it is classified as having no benefit, which means it can't be tested in trials very easily- I am a supporter of the move towards taking this off Schedule One so proper trials can be done across a range of conditions.
It's a bit weird to say there's no cure for HIV/AIDS, there isn't but in the 80's it was a pretty much always fatal disease within a really short time frame, and now, thanks to antiretrovirals, people live decades with HIV and babies can be prevented from getting it from their mothers. That's amazing progress- although the issue of the drugs then not being cheap enough or available enough to the poorer nations and people is then the issue for the pharma companies.
Again, what does it mean cancer can't be cured? Childhood leukemia survival rates have improved and improved due to treatments and now stand at around 90%. Lots of women are surviving longer and longer with breast cancer, many cured. There isn't 'a' cure for cancer as it isn't one thing, but some great progress has been made in some areas- not in others however, and the UK still does worse than elsewhere, not necessarily at the actual pharma/treatment end, but at recognising and diagnosing and getting quick enough treatment, which is not a pharma failure but a systems one.
There is a lot of money to be made from sick people though, and from 'lifestyle' disorders which are ongoing through an entire lifetime such as high blood pressure/cholesterol (e.g. statins), IBS, anti-d's...medicine or rather doctors also manage to kill or create severe side-effects in quite a large population per year as well (iatrogenic deaths), it's the third leading cause of death after heart disease or cancer.
It's complicated and not as simple as 'Big Pharma' bad at all!