Da Blob. Thoughts on your friend observations. All seem to be true.
Is the traditional friendship more likely to turn up where the family is close knit and social groups are fixed rather than mobile? In this case people are thrust together, exchanges occur naturally where some of them may multiply so parties are mutually beneficial to each other and recognize each other as such. Friendships are more likely.
In this mobile and separated age, if that is what it is, each friendship can't be so likely. So as you say, the need to exchange, to be recognized and to interact with others looks for some other outlet. You mention:
1. Rent a friend - you will be recognized, can improve yourself, but it's one-way. You have to keep renting.
2. The media - you recognize others, can bring this info to share with acquaintances and can improve your knowledge.
3. What else?
At the risk of over-interpreting, what about bulletin board forums? Interaction is possible. One can interact and be recognized. It's 1-2 dimensional, not 3. It's crowded so individuals are diminished. There is lots of feedback. When it isn't crowded, feedback can collapse. One-on-one doesn't work unless it leads to 1-on-1 personal messages. Is this a different KIND of friendship? It's a friendship with a forum group, not an individual. Modest social skills ARE desirable, but they are minimal. Is this a new thing? What is missing? What benefits have I missed? What deficiencies are there?
Well, yes an exchange of PMs adds a dimension to online relationships, there is less attention seeking and grandstanding in one-on-one conversations and some might be surprised at who on the forum i have had such exchanges with. It is just rather natural when addressing an audience, or a forum of observers, to put on a 'performance' of some type, that might not even reflect one's true opinions or views.
The destruction of the extended family, at least here in America, occurred in the aftermath of World War II. A social experiment was launched and a Consumer Republic, was fostered (foisted) by the ruling class. This initiative involved the creation of the small nuclear family, a transient lifestyle and the promotion of immediate gratification. Some think that the nuclear family is an old thing, but actually, such a social unit only seem to be around for a single generation, that of the Baby Boomers.
Of course, this 'modernization' of society destroyed all sorts of opportunities for human relationships - isolating family members from cousins, aunts and uncles etc. Also it was assumed that ambitious and compliant corporate lackeys would move whenever and where ever, their employers dictated - uprooting their families and destroying the "Home" with each move. This transient lifestyle, made profit for those who owned the corporations, but was very damaging, psychologically, to those employees and their 'nuclear' families, who had no permanent home - just a series of houses that were lived in...
And of course, the aforementioned media intrusion into private lives seems to have even further isolated family and friends from each other.
Traditional friendship was made possible in an atmosphere where it was possible to trust. One could trust friends - if they were going to be around one's entire life in one's community and long relationships can survive the stresses and strains that are involved in any human relationship. People learned how to work through problems with friends in relationships and grew, matured as social beings in the process.
I think that is one of the reasons people have so much trouble with intimate relationships, there simply is no experience or lessons learned from the mistakes made and corrected in long-term friendships such as misunderstandings, selfishness, seeming betrayals etc.
EDIT: BTW -
A Consumer's Republic by Cohen is an interesting read - worthy of scanning at least...