Because you're not really buying the hardware. Like you are in the sense that the price of the bike covers the hardware cost, and that you own the hunk of metal and plastic so that you're responsible for maintaining it and fixing/replacing it if you break it and it's transferable if you ever want to sell it. But like an iPhone you're buying a client to a larger service hosted by Peleton -- that's their whole business model. If you want an offline bike there are literally hundreds of brands to choose from but you buy a Peleton bike because it's the entry-fee to access Peleton's services.

Every company wants recurring revenue:

https://www.datagubbe.se/endofownership/