This is the nub of the difference between product and service

Hardware clearly falls into the former, and initially so did software. However the last 10+ years have seen commercial software move to a (solely) subscription model which provides recurring revenue and substantial profits

That model is becoming far more pervasive and extends to infrastructure (AWS, Azure etc), and now just wait for it to be extended into new areas like cars (eg: BMW doing subscriptions for remotely turning on seat warming feature in winter)

Where does product end and service begin?

As a consumer i like to buy product and if it’s good - or crucial for me - I’ll happily pay support. Xmind for mind mapping is a great example where i happily pay every year because i use it a lot and as a software developer i like to pay for good stuff 🙂

Support can provide a revenue stream as NVK noted, but that model is dependent on the need for support which tired back to criticality. Consumers don’t generally care too much - businesses certainly do.

Redhat (which IBM eventually acquired) built a hugely successful business providing value add services over open source .. but again .. software

Hardware is a tough one and I’ve never been involved in production but appreciate the skill and effort and the challenge of the pure product model