If each product was made by a different company then switching products might result in lower prices. However even in that case it is not guaranteed. It is just as possible that the company seeing its product is in demand decides to charge more. If you have one company making multiple products they may simply decide to raise prices on the popular product to compensate for the slow sales of another product. In addition the free market concept assumes people switch or give up products easily and willingly. If you have two products that are known to be equally good and one is cheaper, then yes the switch can happen. Of course we then get back to the scenario where the more popular product becomes more expensive.
The situation we're facing now is one where collusion between retailers could actually be a good thing. Together they can decide to break any supplier who refuses to reduce prices. But it is also dangerous because of course once they're colluding they can take it to extremes and squeeze the life out all the suppliers while boosting their own profits. A Walmart scenario.
Why don’t P&P bring down there no name brand products, in fact its more expensive that the branded product in some cases.
Those are manufactured for Pick n Pay, so they're still subject the same supplier increases.
My experience has been that their No Name stuff is invariably substandard, and I've yet to have an item I've not had to return due to the poor quality. But at least it was once much cheaper.
Now personally I could spend time and effort running around looking for alternative products, trying things to see what I can substitute, and certainly I would like lower prices, but they would have to get a lot cheaper to make it worth the hassle.