I still don’t buy any of the examples. In authoritarian regimes, other than the established hierarchy - the party members who have cushy jobs because of the oppression of the government - any base is long ago evaporated. The party beneficiaries would probably be more opportunists than believers, and generally to few to qualify as a groundswell “base”.
The Romanians, AFAIK, did not have a popular backing for their government. Indeed, it had one of the most oppressive regimes, sufficiently hated that unrest turned into overthrow in a matter of a day or less. (The was the protester in East Germany with the placard: “Poland 10 years, Czechoslovakia -10 months, Hungary 10 weeks, Germany 10 hours” and hastily scrawled at the bottom - “Romania, 10 hours”) Elena’s last words were apparently “Nikki! They’re going to shoot us!”
Lady Jane, IIRC, (Someone with a better grasp of British history to weigh in?) was first of all married to Dudley Jr. so it was a power grab by her father-in-law. Combine that with it being the fight between Catholic and Protestant, and the tug of war between religious politics and legal succession, she probably did not stand a chance to begin with. It wasn’t so much that people supported her and changed their mind, as that when Edward died, it was assumed his much older sister Mary would take over despite being Catholic, despite being originally excluded as product of an illegal marriage. Henry and Edward had played games with the succession laws but in the end decided to let the old law and tradition stand - Edward, then Mary, then Elizabeth unless any of those produced offspring. Dudley Sr. gambled that the elite would prefer Protestant over legal succession, and lost bigly. Perhaps too many remembered the War of the Roses only 3 reigns prior, and were reluctant to support a less direct claimant. Some didn’t want Dudley Sr. calling the shots.
Perhaps a better example of how a regime has a base is the Iraqi one - the Baathist party was mainly central Iraqi Sunni’s. They kept under control the southern Shiites (who outnumbered them) and the northern ethnic Kurds. Anyone who wanted a career in government agency had to join the party. The Sunnis recognized that their position was precarious and depended on Saddam’s repression of the others, but despite typical totalitarian cult of the leader, there’s no indication they were adoring fans of the leader - they just tolerated him. And, it was outside forces that did him in.
Of course, no example would be complete without mentioning Hitler. Again, there was a fanatic group of Brown-shirts willing to cause trouble and engage in violence, but the majority of his support - at most, 33% of the votes cast - was because of his violent opposition to Communists and promises to get the economy going again. It was less than 15 years since communists had trashed the Russian empire, executing the elite and confiscating anything of value from the middle class, and fellow travelers were creating chaos in Germany. It was 10 years after gross hyperinflation had destroyed the local economy. Hitler promised to make things better, and exploited xenophobia and prejudice to blame those responsible, for a population looking for blame. Things got better for a while for those who did not oppose him, but presumably enthusiasm dwindles as things got worse. And still … got only 33% of the vote. And like Saddam, was removed by external forces.
I suspect a disillusioned base in a stable dictatorship is more likely to lead to a palace coup. Perhaps we can pick on Mubarak. His regime collapsed because the general population was disillusioned with his government and its blatant corruption. The Army stood back because they disapproved of Mubarak’s attempt to place his playboy son in charge; in the ensuing chaos, the Army itself seems to have not lost the people’s respect, and after some interesting messy (lethal) politics seems to have come out the winner.