The reports of her ill health are, as always exaggerated.
Garland would have been brilliant if MGM had fired the sadistic hack choreographer Busby Berkeley a few weeks sooner. Hell, he should have been fired a few YEARS sooner.
Berkeley was an asshOle to her, making her life hell all over again, as he had done 10 years earlier, when he was choreographing the numbers in the Andy Hardy and "Babes in Arms/on Broadway" musicals she did with Mickey Rooney.
By the end of the 1940s, Berkeley was a washed-up, sadistic (did I say that already?), one-trick pony whose kaleidoscopic choreography was outdated and Garland knew it. She wanted him replaced with her good friend, the young and talented Chuck Walters--and she let everyone know.
In return Berkeley declared war on Garland, berating and humiliating her as he had done in the 1930s. It worked. She started taking more uppers to wake up and downers to sleep, which resulted in showing up late or not at all.
In the end, both lost. Both were fired.
But just listen to her recording of "You Can't Get a Man With a Gun" (audio only) here. She would have been PERFECT:
http://gamerchick02.tumblr.com/post/17579312200/i-listened-to-judys-version-of-this-posted-here