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.
Why don't we have this with computers? Surely we're depriving Lenovo and Apple of such revenue if we use the computer and don't pay a monthly fee? This whole sub thing is nuts.
We do, it's basically Google and Apple's business model with Android [1] and iOS -- they're just better at hiding the monthly fee.
[1] Yes you can have non-Google subscribed Android devices, doesn't mean that Google is banking on all but an insignificant portion of users doing that.
This has already happened in the workplace. A lot of offices have computers that are 'thin clients', meaning they run a very minimal, locked down OS that only lets them connect to a cloud-based Windows environment, managed by an IT vendor like Citrix.
No data is stored on the company hardware, it's all in the cloud.