My current operating theory is that Reagan was blackmailed/threatened into choosing 41 for VP. Not saying RR had guilty secrets to hide. It could well have been threats against family or the US.
My research of how the VP choice happened seem to indicate a different choice until a sudden last minute sleepless night change forced on him. Beware of accounts you read about it because most are written by DS players. What you notice in reading them is mostly the serious lack of a logical explanation for the sudden change. The “explanations” are lame and not credible, IMO.
.... and then the near assassination. At minimum a warning to toe the line.
Richard Allen, who says he was in the thick of things, describes Bush as a last-minute replacement for then-President Gerald Ford, who was negotiating for a "co-presidency", with Kissinger and Greenspan thrown in. Reagan was well aware that such an arrangement with Ford was fatally flawed, but didn't seem to have a viable alternative. Allen suggested Bush, and got an agreement from Bush that he would fully support Reagan's platform, despite Bush's personal support for abortion and antipathy towards supply-side ("voodoo") economics.
Apart from the assassination attempt (!), Bush kept his word -- until he himself became president.
.... and then the near assassination. At minimum a warning to toe the line.