A conspiracy theory? Interesting.
It is much simpler. Times changed and things that were acceptable were no longer. What caused his downfall was the Noos scandal ( even if denied if is common opinion that the RH knew what was going on), the Botswana scandal ( without his accident and what was known after it, things would have been different) and his poor health (the images of his last Pascua Militar were definitive).
I think that those who did not accept JC behaviour simply felt he was needed to keep the new Spanish democracy stable. Once his successor was settled and trained Felipe became a potential alternative to his father. That is when the scandals seem to have come to light and became an issue for the king. In the end they decided that Felipe was a safer pair of hands to trust the Spanish monarchy to then the ageing Juan Carlos.
People may have heard or learned this and that through the years, but knowledge is always cumulative.
At some point the proverbial sh** hit the fan because the people’s accumulated knowledge of JC’s corruption reached a tipping point and the King was suddenly recognized as a parasite that needed to be neutralized.
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