Following the trend...
"Just spitballing here:"
Had a few ideas to add as well as some ideas to add internal depth to my history at the same time (I didn't have a reason for the grandson taking over as opposed to the son, this RP gave me an idea for one):
Pre 1964. The Bustos Family is ideologically aligned with the Rationalists however there would have been elements in the company that would have found the Ascendancy to be potentially more profitable, trade wise. So the AS would have traded with all willing factions with no preference.
Post 1964. Under, then, Chairperson Christopher's (the grandfather) direction, did the AS focus on trade with the Rationalists, using the argument that they were the most likely to win, thus the potential for future and long term business resided with them. Some members of the Board would have pointed to the Ascendancy's initial success, especially during the Purge of '66, as evidence that the Chairperson had aligned with the losing side. There was a small but, influential, movement within the company to replace the Chairperson. When the Rationalist and URDF managed to work together and win by 1969, said Board members and accomplices, were terminated and blacklisted along with certain members of the Bustos Family that were disowned, one of which being his own son.
All of this controversy would have been front page news inside the AS btwn 1964-1969, thus the AS's involvement favoring the Rationalists would have been no secret. This would allow the Ascendancy to have clear knowledge that the grandfather was working against them. Hence the assassination attempt on the grandson?
Post 1971. Trade essentially dropped to a crawl? Is this when you basically shut yourself off from the rest of us or was it when the civil war first started? or even earlier?
Feel free to comment/adjust/clarify.