I dont think Skinner ever claimed to be CWWs friend.
And I believe that MS didnt entirely know CWWs dark side.
IIRC - Skinner primarily had a business relationship with CWW, which started after MS introduced CWW to Skinner because of CWWs computer brilliance. Skinner had business connections to CWW for about a decade, when Skinner was about age 33 to 43. CWW is about 5 years younger. That type of relationship and the timing later in life seems that it would be easy to cut ties.
Its much easier to extricate yourself from an adult business relationship vs a true friendship that started during childhood.
From what it seems, MS was a loyal friend of CWW for more than 3 decades; MS knew about some of CWWs troubles (drugs) but not all of his troubles. Knowing CWW from childhood, maybe MS felt unconditional love for him, similar to a brother or other family member.
Loyal and loving friends dont simply discard a friend, especially during hard times. If we all gave up on each other so easily
. I would certainly wonder what does it mean to be a true friend?
I get your point abut childhood friendships harder to remove yourself from and what loyal and loving friends do when the chips are down. I also think that this is partially a case where there were "the ties that bind".
Knowledge, secrets, hidden past.
Fear of exposure might be what is harder to let go of.
Or, maybe in MS's case never really giving up the past for his new life with TS due to never really being 100% accepted in this new life. Not everyone thinks he is such a prince. The old adage, "you can take the girl out of the country, but you can never take the country out of the girl". This could also be part of the complex nature of him remaining friends. Secrets do bind.
I think it is very the comment by Amazon Rain that MS had not friends (that she was aware of) outside of their friends in common (MS + TS) and TS's friends.
When MS met TS he met his alter ego, IMO, hard working, driven, goal orientated, knew what she wanted to do with her life, had plans, was making her life happen, educated, good looking, from a good family, was going to make better than average money and so on.
He shut down the access to a view of his previous life, because, IMO, she would of not moved forward in her life with the real MS, IN THE BEGINNING OF THE RELATIONSHIP, if she knew who he really was. But then again maybe with all of the second chance and benevolent feelings and actions toward others, she may have considered it. But the big BUT is, its seems she did not know the extent of MS past and his friends and family, she was not a frequent visitor to Missouri, and who doesn't know their husbands best friend? I mean
really know.