Could the Academy screw Joaquin at the very last minute

Yeah, technically the first choice "anything could happen", is true, but assuming he wins everything else, I'm not sure why he'd lose unless maybe something bad came out, but even then depending on what it was, he'd probably still win similar to when Affleck won a few years back, because there's so much love for him and his performance. 

Also agree that this is definitely different than Glenn Close's situation. She almost won just on her narrative alone, but The Wife was basically a no one cares movie outside of her performance. It couldn't get traction anywhere else even for Pryce at BAFTA. Even Leo and Kate won their overdue Oscars for films that were nominated for Best Picture and were stronger than their competitors similar to Phoenix's situation albeit he probably faces tougher competition than they both did, although he'll easily win in the end like they did. 

Even Julianne Moore and Christopher Plummer who were both lone nominees had critics support certainly more than Close got. I think she only won New Mexico and San Diego, and she wasn't a factor at all in the top tier critics awards like Moore and Plummer were. Plus, Moore and Plummer had very fortunate timing that their fellow nominees weren't that strong unlike Close who was up against a beloved Brit whose film tied for the most nominations, and who had won a bulk of the critics awards including the top two critics awards, and Best Actress was one of the easiest places to award The Favourite with an above the line Oscar. 

People have won for shit films that nobody watched in the past, e.g., Lange in Blue Sky. 

anything is possible

Still Alice is far from a shit film. Moron.

Yes, every year is different. There was a feeling that Lange only won Supporting Actress for Tootsie as a consolation prize because everyone knew Streep was going to win for Sophie's Choice, and it became even louder by 1994 since Lange had been nominated 3 times in leading after her win. 

Also I want to say again Lange and also Moore had very little competition. Foster had already won twice. Sarandon was a lone nominee. Ryder was the only above the line nomination for her film. Richardson was also nominated with her costar Rosemary Harris, but Tom & Viv barely got any awards traction outside of Richardson and Harris.

I didn't follow who was more likely to win other than watching Siskel and Ebert's annual Oscar show although I forget if I watched in 1994, and reading Entertainment Weekly and Premiere, but I think the big story was how the best leading actress performance wasn't even nominated because The Last Seduction was disqualified for being shown on HBO before it was released in theaters.

I also don't know what happened to Jennifer Jason Leigh either. She won NSFC, but for some reason AMPAS never warmed up to her until much later on in her career. I don't know if it's because she was too indie, or maybe something to do with her father's death in some way. I don't know, but she got a lot of attention for her two supporting turns in Miami Blues and Last Exit to Brooklyn but missed out in the end. Then, she got attention again in Altman's Short Cuts, but was passed over.  Then came Mrs. Parker and the Vicious Circle, but she couldn't even get a nomination in a weak year despite critics attention and a Globe nomination. She does the more Oscar friendly Dolores Claiborne, but AMPAS doesn't bite at all. Then Georgia happens, but her costar gets nominated instead of her. 

Anyhow I think Ryder was probably seen as too young and someone that would win later on for a more popular film. Sarandon was becoming "overdue", but again I think similar to Ryder they wanted her to win for a better/more popular film which she arguably would a year later. So that left Lange who was also helped by the fact that Blue Sky wasn't released for like two years because Orion went bankrupt, and also because it was the last film that Tony Richardson directed, and of the feeling that she she should have a leading Oscar. She also won LAFCA and placed second at NSFC. 

What does this mean, exactly? 

To be ageist is to be self-loathing - we all grow old.

I guess no one has seen The Trip to Bountiful, Blue Sky, or Still Alice, either. 

I wouldn't say "anything can happen" but I would not rule out Edgerton just yet. He's Phoenix's only competition after all, the movie was a hit, and if Elton John's the frontrunner for Original Song, that might work for Edgerton's chances too. Even if Joker is the most-nominated movie at BAFTA, Edgerton is playing a national treasure of theirs, plus he's hit all the televisied precursors.

But I'm still predicting Phoenix, as I have since September.

Re: Glenn Close and Julianne Moore, I think you have to evaluate stuff like this on a case-by-case basis.

Julianne Moore had won Best Actress at Cannes for Maps to the Stars which gave her a triple crown of festival acting, the second woman and fourth actor overall to do so overall (and still the most recent to this day). She was double nodded at the Globes and was up against only one woman in a Best Picture nod (Felicity Jones, and The Theory of Everything was not popular enough to win both lead Oscars.) In the age of BP expansion, it's quite rare for any acting category to have only *one* acting nod that's also up for Best Picture.

Whereas Glenn Close was The Wife’s only nod, which did not come remotely close in any other category for a nomination. The Favourite had TEN Oscar nods which showed multiple branch support, plus crucial wins in Globes and BAFTA.

(I’m not sure what Close, Moore and Lange have to do with this year's Actor race, but I thought I'd offer my two cents regardless.)

Well Still Alice made twice as much as The Wife at least. But yeah, occasionally someone wins an Oscar from a movie that pretty much no one has seen.