I believe that I understand your point, where is the evidence of a supply-demand curve? Is this just an academic construct suitable only for teaching at university? Or is it real. We have all seen what happened to the price of used bikes in the last year. And used cars are going
up in price because the supply of new cars is down due to that semi-conductor factory that burned to the ground. We know for sure supply and demand are linked, but who knows what the actual "LAW" is? I doubt there is one like the sort of law you get in Physics or Engineering.
However the examples you draw on have different conditions. The toilet paper outage was not due to any reduction in supply, quite the opposite really. It was just panic buying, the retailers knew it and so did the manufacturers, as did most of the customers - but who wanted to be out of TP? That was no time to induce further chaos by increasing prices, although I'm sure some independents will have done so.
But the bike & components problem was both an increased demand from people suddenly spending more time at home and wanting to ride a bike, and reduced supply. The reduction is supply was two fold: one was a deliberate reduction in supply to avoid a forecast demand reduction due to Covid (boy, did they get that wrong!) and also outages caused by factory output reducing because people were ill or isolating.
Also, as
@Gary intimated, bikes are complex items and with a complex and slow to react supply chain, toilet paper is none of those things.
Retail stocks of TP were back to normal pretty quickly, once folk had filled their bedrooms. But the bike and components situation is still poor. I broke my XT 12-speed mech today and the chain was not looking good either. At the trail centre there was a bike shop, so I asked for a Shimano XT 12-speed mech. I was told that they could not get any until January, but we have some SLX ones that have just come in. (Yes please!). Similar response about a 12-speed chain, he only had KMC, all sold out of the Shimano/SRAM ones. Same response from me. He solved my demand problem immediately with something that was good enough. I didn't wait to find out how much cheaper I could get my items on the internet. I wanted a solution now, not in two weeks or two months time, if that!