Why would someone else maintain the adapter? Would they be charging for maintenance (or selling data / network) as well? What company should give their business to somebody else?

I assume writing and maintaining apps across all stack of devices is real work that someone has to do full time with a decent level of quality. Unfortunately, you can't just ship software and call it done, even without adding features, new devices are getting released, new OS versions are getting released, new security updates are getting released, server infra has to be maintained and patched.

I feel that all this work isn't getting appreciated and many think that this should be offloaded to somebody else to be done for free. They already offer a free app with free CSV export.

Also, they just might have taken on too much scope and paying for all that scope isn't sustainable from hardware sales alone, unless people continue to buy, but at some point all who would buy will have their devices and scope can't be covered anymore.

Right, but they need to keep up with those changes to support their continuing sales anyway, so it’s “free” to keep supporting the existing installed base too.