BT is a bad example because they still, to a great degree, provide a great deal of the infrastructure (masts, boxes and cables) via Openreach. To some degree, together with BT, so do the BBC.
Where I live, in the 'valleys', we have a lot of VHF masts on top of the hills. Now, as I have a book on this, some are VHF pure and simple and others include microwave links. Parts of the system are pure communication and part are or were defense based (follows on from WWII and then the cold war). The BBC still looks after (again with parts of BT) the emergency broadcast system. You can also, at least with BT, include the 999 and coastguard stuff.
In more recent years, as our cell phones took off, additional towers NOT owned by either, have sprung up. The EE network (I mentioned earlier) is one and there are others. HMG requires all of the owners, BT, the BBC and EE etc to lease time and use to other companies. The same system is how some energy providers without a single power station can offer us deals.
Now, like Openreach is the 'cable' part of BT the BBC has yet to separate itself from their infrastructure properly. Arguably this is why it stays necessary to pay a license. The other way is to completely commercialize the BBC, having a new entity look after the infrastructure (masts and transmitting kit but not studios) as BT did.
Regarding people not reading contracts... lol. I'd point at the recent United Airlines debacle. EVERY airline can turf you off a plane - all of them. And we all 'tick the boxes' saying we've read and agreed to the T&C. We all do it. Then moan when it suits us. I will say you, at least, wrote in and complained. Most don't. I just stopped watching.