I think the thing that is relevant here is that, as opposed to what life was like at the end of the 18th century, there are now corporations that are so large a

I think the thing that is relevant here is that, as opposed to what life was like at the end of the 18th century, there are now corporations that are so large and powerful that they can control many levers of what it means to participate in society in today's age, and thus constitutional freedoms should apply to them as well. For example, much has been written on HN about how credit card companies essentially control what is acceptable for online content (at least online content that one might pay for). It may be correct as to "the letter of the law" that these companies shouldn't have to abide by freedom of speech or association, but the fact on the ground is that there are nearly no other options if the 4 main CC companies decide they don't want to allow you to take payment (please don't let this devolve into a discussion about crypto...) The US already recognizes this when it comes to credit bureaus - the 3 major bureaus are highly regulated and the types of information they are allowed to collect, use and share is explicitly detailed. I see no reason why phone companies should get a free pass.