Online music and movies: I think this basically all started with Napster which essentially allowed people to steal music instead of paying for it. That seems like a decrease in demand to me. I think an increase in supply in this context would be e.g. an increase in the amount of music and movies being produced.

Low-end smartphones: Apple’s charging record prices for its new iPhones so I don’t think the availability of low-end smartphones caused any sort of crash in the price of smartphones. Rather, it’s a new market category.

Operating system software: I’m not sure what you’re getting at here. The price of Windows has been relatively stable for decades despite the availability of free alternatives like GNU/Linux. Apple stopped charging separately for its OS and now essentially bundles a subscription into the cost of its hardware. I don’t think it’s ever been popular to charge separately for the operating system on mobile phones.